/diy/ - Do It Yourself

Why did they replace the standard - signs with those?

SAC305 or SN100C/Sn100Ni+ (tin, copper, nickel, tiny amount of gallium, Sn99.25Cu0.7Ni0.05(Ge)) for lead-free solder? Anyone tried SN100C?

SN100C info (scroll to "Enter SN100C"):
https://hackaday.com/2020/01/28/lead-free-solder-alloys-their-properties-and-best-types-for-daily-use/

Sn100Ni+ I'm looking at:
https://nz.rs-online.com/web/p/solder/1363148

Adele's fat

>>2624857
> Adele
You are not reliable, it took you a lot longer to post that than you said it would.

>>2625006
>the total ampere rating for the circuit.

right.
in a US 220V circuit, current comes out of one breaker, goes thru the load, and returns thru the other breaker.
it makes no sense to add outgoing and incoming current ratings since it's the SAME current, not 2 diff currents.
chatgpt is a faggit.

>>2625052
I will never understand how profoundly retarded people have to be to even remotely consider using chatgpt for anything at all after test-driving it for a few hours at most. Why do people do this? Worse, why do they actually try to use it as an authoritative voice? How insane is it to even think this makes sense when it can't even add two numbers correctly?

>>2625055
Blind faith in media hype and le progress. They deserve what they get.

Remember shitpost about LED autism?
I've received Chinese sunlike LEDs.
It is really interesting, blue and violet chips (which are way too small for rated current but whatever). Original Seoul semiconductor uses only violet chip IIRC.
CRI seems to be good to eye, but feelings are feelings, hard to say.

Other quirk, at low currents violet chip is off. Makes sense as violet chip should have higher Vf.

>>2625062
Remove the phosphor so we can see what the fuckyou’retalkingabout

>>2625062
>CRI
That's an objective thing.

>>2625068
CRI is pretty well defined, it basically compared distance between black body radiation and light source for selected number of colors.
>>2625066
I tried, but every time I was breaking bond wires. So RIP 5 LEDs. But you can see on the projection to wall that there is a violet-ish spot and blue-ish spot

>>2625095
It's objective, so your eye can't judge it. I know I'm exaggerating slightly, but you know it's true. So did you verify the CRI?

>>2625097
>So did you verify the CRI?
I dont have any sort of device. So unfortunately no.
>It's objective, so your eye can't judge it. I
I can tell CRI 80 from CRI 90 kinda. With CRI80 telling apart metal film tht resistors is hard, and with CRI90 is bit easier.

Does anyone know what -12V is used for in older (mid 90s) computers? I want to replace the stock power supply in one with a modern SFX supply.

However, it seems that modern PSUs actually are rated for lower amperage on certain voltages. On 12V, modern PSUs are rated much higher. For example:

-12V
0.85A on old PSU
0.30A on new PSU

+5V
48A on old PSU
20A on new PSU

+3.3V
41A on old PSU
20A on new PSU

+12V
11A on old PSU
54A on new PSU

the 5V and 3.3V I am not too worried about, as I can simply regulate them down from the bountiful 12V line.

But for -12V, I am not sure what to do. I'd prefer not modifying the internals of the new PSU. I figure my options are:

1) somehow get -12V from the +12V rail
2) run a separate independent -12V power supply
3) hope that whatever on the board that requires -12V never pulls more than 0.3A

If going with option #2, would I want to tie the ground output of the 2 PSUs together?

>>2625194
>what -12V is used for in older (mid 90s) computers?
RS232 serial and PCI bus (for expansion cards that require -12V)

>>2625194
Do modern computer motherboards use DC-to-DC converters from 12V directly to their 1.8V and such rails?

Have you noticed that JST PH connectors are 2.5mm on aliexpress? The standard JST PH is 2.0mm. And JST EH is 2.5mm but it is a different style connector.

>>2625194
>what -12V is used for in older (mid 90s) computers?

besides rs-232, some internal sound cards (and ISA bus soundcards) use -12V for some audio chips.
most likely everything will work fine even with no -12V supply at all.

>>2625198
yes. modern PSUs provide only 4 voltages; 3.3, 5, 12, and -12

>>2625198
Depends on the power supply. Laptops buck the 19-20V down and then regulate the rails. Desktops use the 3.3V from the ATX PSU and regulate it down to the necessary CPU/RAM voltages. 12V is typically used for hard drive/optical drive motors, fans, etc. while 5V is for the logic boards, USB bus, etc.

>>2625209
I meant in comparison to stepping down from 5V or 3.3V. Because the shift away from powerful 5V and 3.3V rails towards powerful 12V rails as seen in this anon's old vs new comparison suggests either that, or that they're using more powerful things that have always run on 12V (maybe graphics cards?).

>>2625211
Ok so they do use 3.3V for the CPU and such.

>>2625206
the computers in question are old Macs. They don't use RS-232 that I am aware of, but they do use SCSI and ADB. I also don't believe they have any sort of ISA bus, but they do use all PCI slots.

They might have some sort of carry-over bus from NuBus, but I think they use what's called a "600 bus" for the various interconnections on the mainboard.

>>2625194
Probably nothing. Maybe com port or sound chip.
>>2625198
Yes, there is 12V only standard.

>>2625198
Yeah, imagine what amperage a 500W GPU needs at 1.1 volts, and figure out how thick the AWG would need to be to minimize the voltage drop at that ampacity from an external PSU. You’d need busbars, not wires.

>>2625225
Firewire also provides +12.
It’s almost like it was sensible. Let’s kill it!

I am an extremely high libido individual. I plan on making a battery powered circuit which connects to a solenoid linear actuator which oscillates the solenoid shaft horizontally.
I want to have the solenoid shaft be connected to something which goes on my benis (like a pocket bussy but not exactly).
How do I go about obtaining/making a soft phallic orifice that can be removed and washed easily but it's still comfortable to wear on my penor and hopefully not leech carcinogens in my body. What material would it even be?

>>2625306
Food-grade casting silicone. Make a mould out of 3D printed plastic, plaster, moulding clay, corn cob covered in clingfilm, whatever works for you. Then mix up the casting silicone and pour it in.

The electrical design is somewhat straightforward, just an H-bridge and microcontroller. A safe but effective mechanical design is going to be the hardest part.

>>2625316
Yeah i can handle the electronics and software, I've made similar H bridge boards for switching much larger inductors. I've decided on using two IR2104 for the bridge and an ESP32 to connect using BLE to my phone (to control speed etc). I live nRF52 but ESP32 is just easier to use
Still trying to find good logic level FETs to use, battery is a 3.7V lithium ion so Vgs will need to be low (don't want to put a charge pump to generate higher voltage)

I'll look into food grade silicone. I'm scared of chemicals being in contact with my skin but hopefully it'll be fine

>>2625013
This is lead free "Adele is fat", it was a bitch to solder

>>2624853
>>Recommended Design/verification tools:
>KiCAD 6+
Any obvious improvements in 6 vs 5 or 7 vs 5 or 6? I took a quick look and just noticed different icon styles.

>>2624853
How would a total noob like me with zero knowledge of electronics become a 100% natural beast?

>>2625410
YWNBA100%NB

unless you're a natural beast.

>>2625052
>it makes no sense to add outgoing and incoming current ratings since it's the SAME current, not 2 diff currents
Ideally, the currents are the same
If the currents are ever not the same, then current must be flowing to ground through some unintended path, like through some dipshit who just touched a bare wire

>>2624857
Best lead-free solder is one that contains 40% other metal and melts at 183-190C

>>2625410
Look at some of the books in the OP.
You can pirate them at https://libgen.rs/index.php

I first learned by getting an AS Level, then an A Level in Electronics, using these two workbooks.
https://www.eduqas.co.uk/qualifications/electronics-as-a-level/?sub_nav_level=books#tab_resources
There isn't much derivation, (partly because at that point we hadn't learned the mathematics behind a lot of things, like calculus) so there are a lot of plug and chug equations.
This should take you from absolute noob tier to at least beginner tier.

>>2624857
>Sn100Ni+
I use that one. Seems ok, but I set my soldering iron to 400°C.

>>2625461
What is it called?

>>2625466
>What is it called?
Aliexpress lead-free alloy containing 40% lead. (actually I dont recommend getting solder from ali as sometimes you can get absolute garbage)
All lead-free is about the same when it comes to soldering. Either doesn't flow as well as leaded (SAC305, SAC0307), or is much weaker than leaded (bismuth alloys).
I dont know about Sn100+ alloys, but I think that <1% of random methods is a homeopathy tier alloy that does perform marginally better than pure tin (as melting temperature is still >190C).

I mean you can try, roll of solder isn't that expensive and most definitely it would work just fine, but why would you use lead-free solder if leaded one is available? Just don't lick PCBs and get a separate toothbrush for cleaning PCB.

>>2625398
Haven't updated the OP since 7 came out. Generally there's nothing but improvements as you upgrade.

>>2625411
>100% Nb
That's a really strange soldering alloy, man

>>2625478
I don't want fucking lead all over my shit if I've been soldering my whole life and will continue to. Little solder beads fly around, pieces of soldered joints I snip off with pliers, lead dust when I have to file through solder which is occasionally.

>>2625548
Lead dust is the worst argument. ALL dust, even non-metallic but let alone all metallic dust, is very bad for you. Lead is the least of your concerns in this scenario, AND we have effective protections for this.

>>2624853
Cupacitor!

Absolute retard here. Bought a mod kit for my GBA, as well as a soldering kit and I need to remove the capacitor in the picture. From the sound of it I can simply heat up the solder on one side and bend the capacitor so it is not in contact with the board, but still connected partially. Will this cause me any issues? I'm nervous, and have zero experience with soldering and de-soldering, but I want to get this screen installed asap. I also read that some people have simply used side cutters to snip off the capacitor, but that sounds like a way to possibly damage the board as well.

>>2625673
>bend the capacitor so it is not in contact with the board

that'll never work.
those caps dont bend like the fat tubular ones do.
you gotta heat both sides, while applying new solder, then shove it off.

>used side cutters to snip off the capacitor

if you have good sharp cutters, with a fine tip, that'll work fine.
if you only have some old wire cutters, they'll never bite, so you'll end up wrenching it off.
which could damage traces.
what i'd do is use a sharp x-acto to sever the lil vertical line just south of the cap.

>>2625685
Good to know, thanks. I was going off of the pictures from the official tutorial made by the kit creators, but what you said makes sense. I have a pair of God Hand cutters for model kits that is probably sharp enough to trip the capacitor. Apologies for my ignorance, but I'm not sure of which vertical line you were referencing.

>>2625691
I mean, you have to desolder it from both pads in order to move it up like that. Why not just take it out and not put it back on again? Or would you plan on undoing this mod?

He means to cut the thin copper trace coming from the bottom of the lower of the two pads. Which is even more permanent than just cracking the cap with your cutters.

>>2625696
Ah, yeah no. I'll just see about cutting the cap off. Messing with the trace seems like a recipe for disaster. Provided it works well, which ideally it will (knock on wood), I'll be sticking with the mod. I wish I had a working 32 pin console so I could skip cutting off the cap or desoldering it, but the one I have powers on but does not stay on, and I have had zero luck figuring out what is wrong with it.

>>2625699
If you cut through the cap, you should be able to easily desolder each half of it. If you ever want to undo the mod, you can just buy a new cap for a fraction of a cent and slap it on.

Would you mind elaborating on what the mod is meant to do, and how that helps you with a console not powering on? Or is that a different console?

>>2625702
>If you cut through the cap, you should be able to easily desolder each half of it. If you ever want to undo the mod, you can just buy a new cap for a fraction of a cent and slap it on.
>Would you mind elaborating on what the mod is meant to do, and how that helps you with a console not powering on? Or is that a different console?
Are we talking cutting the cap itself? Vertically or horizontally? The mod is a backlit TFT screen from a DSI. https://funnyplaying.com/collections/product/products/ita-agb-tft-backlight-laminated-kit..

Also to be precise, I was talking about two different units, sorry for not being clearer. Bought the non-functioning one off ebay and it worked great, reshelled it and it worked fine, only to abruptly stopped working some time later. There is no obvious board damage, and buying a multimeter to attempt to check it did not do much due to me being clueless.

If I find an electric motor out of an old electronic device can I "reverse" it so it produces electricity, therefore allowing me to hook it up to a fan on my apartment balcony and make a mini wind-turbine.
Furthermore, what's stopping me from having magnets spinning around a copper spool and the copper spool then having its wire be fed out to power electronics?
Yes, I have no idea what I'm doing.

>>2625705
The cap itself, vertically. Cutting through just the brown ceramic bit, to make a gap somewhere between either metal contact of the cap.

>The mod is a backlit TFT screen from a DSI
Oh that's cool.

>only to abruptly stopped working some time later
I'd suggest maybe reflowing a bunch of potentially stressed solder joints. Also consider getting a cheap USB logic analyser to up your troubleshooting game.

>>2625717
>>>2625705 (You)
>The cap itself, vertically. Cutting through just the brown ceramic bit, to make a gap somewhere between either metal contact of the cap.
So, like the black line in pic related? Avoid the metallic bits sandwiching the ceramic? Sorry, I'm constantly being reminded how ignorant I am with electronic stuff like this.

>Oh that's cool.
Yeah. I've got a collection that I have slowly been building since I was a teen twenty years ago to play through. It's horribly archaic and primitive by modern standards, but a gaming console that runs off of AA batteries and does not require online access for patches/possible delisting of games is pretty valuable in my opinion.

>I'd suggest maybe reflowing a bunch of potentially stressed solder joints. Also consider getting a cheap USB logic analyser to up your troubleshooting game.
That's a good idea, thanks. I guess I need to decide between being impatient and testing the screen/modding a 40 pin, or waiting and trying ot fix the 32 pin where I do not have to do capacitor surgery, but might end up with a bricked machine or a screen that is bad and past return/warranty.

>>2625723
I mean vertically with respect to gravity if the cap is flat on the table, not vertically with respect to your image as if it were hung up on a wall. My mistake for not being able to describe things well.
Your aim should be to crack the cap so bits fall apart, not force the cutters in like a wedge. Wedging will be more likely to delaminate the SMD pads.

>a gaming console that runs off of AA batteries and does not require online access for patches/possible delisting of games is pretty valuable in my opinion.
In addition, the gameboy is a more modern-styled architecture compared to the NES or SNES, while being less complicated than something like a PS1. This makes it a prime platform for developing homebrew games, of which I think there's quite a few. Not that custom NES games aren't cool at all.

>>2625691
>I'm not sure of which vertical line you were referencing.

lil red line is the trace that connects the cap to the rest of the circuit.
if you snip it with a knife, it's the same as removing the cap.
however, it's not permanent.
to restore it, you just scratch off the green paint, and bridge the gap with a tiny blob of solder.

>>2625734

check this video at 1m4sec
https://youtu.be/sXhyMUO4q3A?t=64

>>2625728
>I mean vertically with respect to gravity if the cap is flat on the table, not vertically with respect to your image as if it were hung up on a wall. My mistake for not being able to describe things well.
>Your aim should be to crack the cap so bits fall apart, not force the cutters in like a wedge. Wedging will be more likely to delaminate the SMD pads.
Gotcha, makes sense. I'll be super careful.

>In addition, the gameboy is a more modern-styled architecture compared to the NES or SNES, while being less complicated than something like a PS1. This makes it a prime platform for developing homebrew games, of which I think there's quite a few. Not that custom NES games aren't cool at all.
Exactly. The GBA is an incredible homebrew platform. Frankly it's a solid 10/10 machine, with the only real flaw being the non-backlit screen, but that's easily fixed these days. Granted, I'm still a bit old fashioned and prefer the reliability and flexibility of AA and AAA battery powered devices over everything having an integrated rechargeable.

>>2625734
>lil red line is the trace that connects the cap to the rest of the circuit.
>if you snip it with a knife, it's the same as removing the cap.
>however, it's not permanent.
>to restore it, you just scratch off the green paint, and bridge the gap with a tiny blob of solder.
I was honestly unaware that scratched/damaged traces could be fixed like that. That might be my best bet overall. This thread has been a huge help, I greatly appreciate all the input and advice that has been given to me.

>>2625736
geez, they almost got the solder mask over the hole

>>2625738
>and prefer the reliability and flexibility of AA and AAA battery powered devices over everything having an integrated rechargeable.
The true chad-pill is putting LiFePO4 14800 cells inside the thing, with a dedicated charge control and protection circuit. Those things will last decades, and when they finally go you can swap them out for new ones. Even Li-ion (NMC) 14800s will probably last reasonably well. Plus these lithium cells tend to leak less often than normal alkalines. Soldered-in rechargeables is just asking to make it more disposable.

Moron here, please help me out.
>have a mp3-player from 3 years ago
>dead battery
>want to replace it
>find bl-5c batteries for phones
>original battery supplies 3.7V, bl-5cs supply 3.7V, should be a match right?
>don't want to fry the board
>charge the device with original battery
>power it on
>try to read the voltage between + and -
>nothing
???
>too afraid to disconnect original battery, and try the bl-5c one.

Can someone re-assure my paranoid mind, that using the bl-5c batteries is fine or hint to a mistake and prevent me from destroying the device?

The end goal is to 3d-print a new bottom for the player with interchangeable bl-5c batteries.

pic related, the board

>>2625723
use a big flat tip heat up both sides use the smallest tweezers you can find (less grip == less likely to delam pads). if you get them both warmed up you can then jump between them to keep the solder fluid on both sides

Game Boy mod Anon here, just want to say thanks again for the help from last night. I'll try scratching the trace once I'm properly awake, and post results and pictures of the completed build later on.

>>2625755
I had no idea that LiFePO4 batteries existed. Found an interesting article about them. Not sure if I will use one like you suggest, but I'll do a bit of research on them. Thanks.

>>2625812
>use a big flat tip heat up both sides use the smallest tweezers you can find (less grip == less likely to delam pads). if you get them both warmed up you can then jump between them to keep the solder fluid on both sides
Much appreciated. I'm going to try the trace scratch method that >>2625734 brought up, because it seems the safest when I consider my current lack of soldering/de-soldering skill, but if I get comfortable with soldering I might fix the scratch and carefully remove and bag the cap.

>>2625807
if you can, replace it with AAA, or, even better, AA, since you’re 3D printing anyway.

Replace the charging circuit to NiMH (or whatever) or block off the (probable) microusb if you’re just going to make the batteries accessible.

Also investigate if the device is up/down converting the 3.7 volts from the battery (I see a coil on there) and kill that circuit too and just use batteries directly.

The batteries will last a lot longer in the device itself if you use boosting headphones. I had a pair that takes a single AA cell in-line with the cord, and I’d just use a rechargable NiMH cell that lasted for over a week and the player lasted months without recharge.

Is there a way to improve the gain of or solder in a replacement antenna for a PCB such as pic rel? tl'dr: new bluetooth device otherwise performs great, but has dogshit range compared to its predecessor. Thanks in advance for helping this brainlet.

>>2625807
>original battery supplies 3.7V, bl-5cs supply 3.7V, should be a match right?
Should do. Can confirm have run portable lights and stuff off repurposed old phone and camera batteries. My daily driver bluetooth receiver has a battery from a 'disposable' vape pen even.
>try to read the voltage between + and -
>nothing
Are you sure there was still voltage coming from the battery when you measured? That battery has a protection circuit under the kapton tape which disconnects the terminals if it under/overvolts

>>2625306
There was a thread last year I think by another anon who did something similar with a linear actuator.

>>2625916
>replace it with AAA, or, even better, AA
I decided against them, because they are too thick. I have some ikea ones nearby, but I'd need to stack three of the AAA ones to reach 3.6V.
The battery I chose is less than 6mm thick, and the remaining dimensions align almost perfectly with the player.
>block off the (probable) microusb if you’re just going to make the batteries accessible
I'm confused. Why would I do that? The connection of the usb-port is neccessary to transfer files to my pc and enables the device to play while being charged (with the current battery at least)
>(I see a coil on there)
I am unexperienced and maybe blind, can you mark it on the picture?
>boosting headphones
never heard of those. I am usually connecting simple iems.
>a single AA cell .. NIMH
for which voltage is it rated? I can mostly see 1.2V ones on amzn. Maybe some outliners for RC-stuff, but they are expensive (20€ for 4 pcs)

>>2625960
>run portable lights and stuff off repurposed old phone and camera batteries
Oh nice, that sounds good.
>protection circuit under the kapton tape
I removed the tape and measured at the terminals, pic related. Also: At the micro-usb-port between VCC to GND there is a voltage of 4.34V (while charging). I would take a wild guess, that the protection-circuit is already integrated into the bl-5c, similarly to conventional rechargeable AA(A) batteries. I think you are not able to buy bare cells on amzn anymore, which undervolt and start a fire.

>>2625979
>I removed the tape and measured at the terminals, pic related.
If there's voltage on the pack's output, and it's wired into the board, then that voltage must be on there somewhere. Can you provide a clearer photo of where those wires are going into the PCB?
>I would take a wild guess, that the protection-circuit is already integrated into the bl-5c
It should, yeah. Usually it's under the black plastic shroud the also houses the out-facing terminals.
>similarly to conventional rechargeable AA(A) batteries
If you mean those lithium ion cells that pretend to be NiMH/alkaline, then yeah. Most rechargeable Nickel cells don't bother with protection since that chemistry tolerates a lot of abuse.

>>2625988
>that voltage must be on there somewhere
Yea, that's what is bothering me. I expected the battery-voltage at the solder blobs, where the wires end.
>Can you provide a clearer photo
I tried, sadly my battery ran out, so further pics will have to wait till tomorrow.
>Usually it's under the black plastic shroud the also houses the out-facing terminals.
perfect
>If you mean those lithium ion cells that pretend to be NiMH/alkaline
Yes, exactly. From what I remember, there was a trend 10 years ago to buy bare cells cheaply on aliex and shove them into the cheapest powerbank-chassis, which usually contains the protection circuit to save a few bucks.

>>2625999
Did you test both with and without the usb plug in? Otherwise, it looks like a lot of flux/dirt/glue/whatever gunk on those beads. Could be insulating the solder from your test prongs. Try brusing the metal bare with something stiff and non-conductive and test again.

forgot to reply to this;
>2623633
yeah that looks exactly like how I built it
guess it's the input cap making the pop?

My GBA board was different than the one in the pictures I posted. Found C54 and clipped it, proceeded to install the new screen and shell, but it's acting peculiar. Troubleshooting it now.

forgot to reply to this;
>>2623633
yeah that looks exactly like how I built it
guess it's the input cap making the pop?

>>2625861
LiFePO4 chemistry is pretty good, but the lack of cheap and available charge control circuits is a shame. No obvious TP4056 equivalent. For a DW01 equivalent that can work with literally any chemistry there’s the TPS3700, but it is more expensive. Well if you have room for a micropower comparator and reference plus some passives that’s also a way to go.
For a charge circuit it’s the same but with a quad RRIO op-amp.

>>2626027
Does that stand for Game Boy Australia?

>>2626028
Yeah the input caps can do this, but R2 should prevent the pop. Is the audio source popping at all?

>>2626111
>LiFePO4 chemistry is pretty good, but the lack of cheap and available charge control circuits is a shame. No obvious TP4056 equivalent. For a DW01 equivalent that can work with literally any chemistry there’s the TPS3700, but it is more expensive. Well if you have room for a micropower comparator and reference plus some passives that’s also a way to go.
>For a charge circuit it’s the same but with a quad RRIO op-amp.
That's all Greek to me, but I think if I do some research I'll figure it out. Thanks for the rundown.

>Does that stand for Game Boy Australia?
Yeah. Sadly I somehow damaged the ribbon cable a bit after taking that picture. Tore the system down because the screen was not showing as centered so I could solder the optional button controls and somehow the ribbon cable tore slightly and now video is fucked. I probably could try to RMA it, but it was my fault and I would feel guilty trying to Jew Aliexpress for a new cable. Life is just one expensive fuckup after another.

If you have an IC symbol with lots of pins, what pin arrangement is preferable, logical or physical?
I would prefer grouping pins together, VDD, VSS, ports, etc. OTOH a symbol that mimics the footprint could make routing easier.

>>2626146
>logical or physical?

logical is best for readability by humans. (i.e. everyone who's not Peruvian)

>mimics the footprint could make routing easier

routing is done based on a netlist.
it's not a drawing, it's a table.

I'm building an ebike battery and on the left is the tutorial im following.

On the right is the diagram on my BMS

On the bottom is what the measurements are.
Why is the voltage across the charger different from the voltage across the discharge connector?

>>2626146
The process of pinout refining is usually sufficiently short-lived (e.g. a few hours) that it's not too bad to use a purely logical method. And this is especially good for ease of circuit reading for things like op-amps and logic ICs, where you have multiple elements per IC that you want to seperate. That said, for microcontrollers where there's little logic besides "V+ at top and V- at bottom", you don't really gain any benefit from having all your pins of a given port right next to one another, unless you're doing direct port writing or reading of parallel numbers. So when you have a bunch of pins that are basically interchangeable aside from name, yeah arranging them in the order they appear around the chip is handy. But there's no reason to go all the way and do the same with your voltage input pins. And if you have pins that are only inputs or only outputs, then putting them on the same side as one another is probably going to be optimal for legibility's sake.

>>2626213
Obviously your meter is interfering with your measurements, since 46.53 - 48.08 ≠ 0.418. Examine your BMS if you want the real answer, chances are there's diode drops through FETs (or through diodes I guess) going on. You can also add load resistors to the parts you're measuring to see what effect that has, or just put 10MΩ resistors everywhere except for where your DMM is to even out the phantom currents.
>inb4 1MΩ input impedance meter

What's the end-game to this measurement anyhow? Either it works or it doesn't. Are you trying to understand how it works?

This thread sucks because of the retarded zoomer trannies who can't figure out how to use a fucking search engine for fuck's sake. Hurry up and kill yourselves.

>>2626213
>why does the voltage drop across the thin charge wire which hass less csa and higher impedance hmmm....
is a mystery anon

>>2626232
>>2626246
ok thanks for the answers. I dont know much about electronics and just want to make sure I havent made an incendiary grenade by accident.

The tutorial I was following said the charger voltage and discharge voltage should be the same.

It must be some voltage drop across the bms diodes since the charge wires are beefy

How do I make a circuit which turned on one led and off another one if I press a switch?

>>2626272

>>2626277
nope. right side diode is always on.

>>2626277
Thank you but I was thinking about alternating. If one is on the other one is off.

Does anyone know if building a diy microphone is hard for someone who has never done diy before? Similar to this video https://youtu.be/4hFuaYfG_FE I dont know anything about microphones or soldering or electricals

>>2626272
bistable multivibrator
>retarded name ^

>>2626277
Oh well I ended up doing that one, I think the alternating LEDs might be a bit too complex for now.
https://youtu.be/Yn88GEnBF0E

>>2626272
It's trivial if you have a switch with both NO and NC contacts.
Wire one LED to the NO, and one to the NC. Common can be either positive or negative, depending on what is more convenient to you.

>>2626279
>If one is on the other one is off.

simplest way is a single pole, double throw switch.
SPDT for the cognoscenti.
you can get them as slide switches, toggle switches, or temporary push-buttons, or permanent push-buttons.

>>2625410
>>2625464
Also see some of the resources listed here https://www.eevblog.com/forum/beginners/electronics-primers-course-material-and-books/

>>2624853
https://watchdominion.org/ https://watchdominion.org/
https://watchdominion.org/

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>>2626272

>>2626386
>>2626407
Before I spend a lot of money on parts does anyone know which one of these works best. THANKS!

>>2626419
the parts would cost pennies and both images are literally the same circuit

>>2626421
THANKS!

>>2626419
>which one of these works best.

it's the exact same circuit.
one is all symbols, the other is more real-world looking.

>>2626426
THANKS!

>>2626237
I see what you mean

Anyone here ever lichtenburg burn wood? I got a 10kv chinese power supply hooked up with leads across a piece of wood on a rubber mat on a wood table outside. I sprayed it with water, im gonna turn it on and off using a foot killswitch 7 feet away and unplug it before touching the leads with rubber gloves, is there anyway its gonna do something crazy like shoot a giant arc or somehow energize through the mat and table and concrete through me? Obviously i already know thats unlikely but just wanna ask if im missing something

>>2626517
>is there anyway its gonna do something crazy like shoot a giant arc
Yes.
>or somehow energize through the mat and table and concrete through me?
Yes.

Be afraid.

>>2626517
No it's perfectly safe. You don't even need the gloves, don't worry, just make sure the wood surface does not keep in contact with the ground at all.

>>2626517
You're probably going to sudoku like that retard who jumped off a ship into the ocean at night. Bye-bye.

>>2626517
That's literally how people kill themselves.

>>2626537
Most people who die are touching hot leads, I don’t see how the wood on a rubber mat on a wooden table can kill me if im standing multiple feet away

>>2626539
>I don’t see how
exactly

>>2626542
Explain how then

>>2626544
How is your "foot killswitch" hooked up? Post a schematic of your setup.

>>2626517
>lichtenburg fracking
>chinesium PSU
F

>>2626545

>>2626557

that looks safe to me

>>2626563
where does it say they weren't holding hot leads while doing it, if you go on youtube most the tutorials are boomers holding the leads. and 2 of those are unrelated.

>>2626564
I SAID IT LOOKS SAFE TO ME CAN YOU READ AND YET YOU WANT TO PLAY WITH DEATH lol do eet

>>2626557
https://www.circuits-diy.com/optocoupler-relay-driver-with-pc817-2n3904/

You need electrical isolation an a normally-open momentary switch so when you let go (after the shock) the circuit is broken.

>>2626576
kek

>>2626576
wheres this shock gonna come from

>>2626592
It will come from the circuit being wired backwards and upside down because the focus is 100% fuggin fragtals and 0% learning the dangers of HV mains-connected chink flesh evaporators.

>>2626597
how is it wired backwards

>>2626601
i don't know
how would you feel if you didn't eat any food yesterday?

>>2626576
>You need electrical isolation

those are typ rated 4000V, so not even slightly useful here.

>>2626604
Anon... you weren't supposed to sell the plot so short. Now the retard won't kill himself after setting up a placebo.

>>2626604

>>2626517
the good way to setup a kill switch for high voltage is a pressure activated switch and a foot operated little airbag. Photonic induction uses one in this video
https://youtu.be/0mGhhdPgXG8

>>2626557
Here's an idea: put the on/off switch on the low voltage side, not the high voltage side. Here's another idea: draw a schematic that actually makes sense.

>>2626612
it is on the low voltage side, the power supply is a 1:10 step up transformer, the low side has a normally closed switch and i added a 7 ft normally closed footswitch with a male and female plug in between it and the 120 outlet

>>2626616
1:100

What electronical component should I google if I want to make a dial? It is not potentiometer since I want to be able to rotate it more than a full turn, infinitely

>>2626622
Rotary encoder. Though there's some cool videos of people making them with stepper motors or brushless servos (or maybe just BLDCs via sensorless operation).

>>2626624
Thanks anon

>>2626386
>>2626407
>>2626419
do it with cmos logic, anon, for the learn and for the lole. switch could be non tactile, theremin style, cmos too.

diy newfag here, I have had a desire to learn how to work electrical for a few years now. This is my first diy, a 50 cent speaker horn wired to a aux cable I cut. I heat shrinked each wire and then heat shrinked everything together for integrity. This felt way too easy and I want to learn more in depth wiring using electrical components but have no fucking idea what kind of things I am able to make. What is some easy shit an idiot can tinker together with easy to find parts?

would this layout be functional? this is going to be on a 4 layer board. vin top pour, gnd bottom pour, one internal signal layer, and one layer for a split B+/B- pour. this will be driving a string of 8 LEDs in series at 20 milliamp so i'm not sure if polygonal pours are necessary? these are 0.5mm traces.

https://datasheet.lcsc.com/lcsc/1912111437_RYCHIP-Semiconductor-Inc--RY3730_C370887.pdf

Has anyone built their own sprinkler system controller? I have an old Toro controller that I want to replace. I am not really sure where the electronics meet the mechanics, in the valves? There are six zones, and six valves. There must be some kind of transducers in between that open/close the valves according to the timer, and that's it? I couldn't find any electrical diagrams that would explain how to control the valves. The interface is absolutely atrocious, some actions are not very intuitive and I'd like to be able to control it from my phone.

>>2626701
There are electronic valves called solenoids that are screwed into the PVC underground. Each station is controlled one at a time by a relay on the control board.

Timer on > relay energized > solenoid powered > valve opens > water flows

>>2626703
Holy shit. That's easy as fuck. I also found this diagram, not my model, but should be the same idea. I'd just need to measure input voltage to the valves, and I guess I could just experiment by powering them manually. Of course a bigger concern is if it is even legal to use a DIY sprinkler controller since I have to have it winterized / dewinterized professionally including the backflow test otherwise it is a $$$ fine and I am afraid they are going to refuse to touch it and call 911 lol. So my plan is to keep the old one in place and add another controller in parallel. Or most likely I will cool down and say fuck it (as I usually do). Freedum is not free.

>>2626708
If you look behind the panel you'll see a transformer, probably 24VAC. That gets rectified on the mainboard for the logic, but the solenoids are powered straight from the transformer.

>>2626708
I guess another approach is to go for a headless design, if there is room in the box, tuck in my own wifi based controller board that could be controlled by the phone and wouldn't affect the standard controller, unless they are activated simultaneously. And maybe add a little switch that would enable/disable it.

>>2626712
> probably 24VAC.
yes

> solenoids are powered straight from the transformer.
So what does controller activate, a relay inside the box? And the relay feeds 24VAC to the solenoid?

>>2626715
Yes, the controller/timer switches the relays in chronological order.

>>2626712
>but the solenoids are powered straight from the transformer
Not him, but why would you switch a solenoid using AC? You can't use a simple diode to stop the inductive spike anymore, you either have to use a TVS or zener setup, or use an RC snubber network. And those RC snubbers get kinda large.

>>2626717
>controller switches transistors that switch relays that switch solenoid valves
can't you just skip the relays?

>>2625062
Well, anon was correct about inrush, it did blow 10 ohm resistor, but not because of energy, but because of voltage rating.

>>2626732
>why would you switch a solenoid using AC?
The solenoids are isolated on the AC side.
>You can't use a simple diode to stop the inductive spike anymore
The inductive spike from the solenoid to the high-side of the relay? The logic side of the relays is where the diodes are.
>can't you just skip the relays?
If you want to spend more money to do the same thing, sure.

>>2626733
>>>/wsg/5122878

Light is weird. It looks yellowish to eyes, but phone thinks it is 4000K. (phone is cross-referenced with laptop screen (6500K), incandescent (2700K) and OSRAM JELMS2 4000K LEDs)
Binning is meh, it is acceptable, but at really really low currents you can see some LEDs not turning on. Maybe it is the nature of dual chip LEDs, maybe those are rejects, who knows. .OSRAM, on the other hand, has 100% perfect binning and 2 years later LEDs still exactly matched.
I've compared this LED to sunlight, couldn't see any difference, phone couldn't see either. It is about the same as early morning or evening sun.
But yes, light/color output is pretty good. On macbook motherboard, you can see difference between tracks and just soldermask. With normal LED (CRI 80) this is pretty hard and you need more light,
Other interesting phenomenon is that you can see just better in general. One LED (idk light output, no more than 20 lm) provides very little amount of light, but you still can see stuff. With OSRAM you get more light (because duh, 180+ lm/w) but you can't see as well.

Chink LED good. I will order more. And different CCT too, so I can make sun indoors and never open windows.

>>2626737
>>2626732
Not sure I understand, are you suggesting controlling AC with a transistor? Or you are talking about driving a DC solenoid?

>>2626742
https://www.electricsolenoidvalves.com/blog/ac-vs-dc-solenoid-valves/

I'm suggesting switching AC to the solenoid with a relay.

Damn, there is an open sprinkler project, with firmware and everything. Anything you could think of, there is already a solution for it.
https://github.com/opensprinkler

>>2626743
Yes that's what I would do but this anon
>>2626732 suggested skipping the relays and use transistors.

Also, apparently 24VAC solenoids can be controlled with 12VDC. There is a long discussion here https://rayshobby.net/wordpress/understanding-24vac-sprinkler-valves/
But it sounds too risky, since the power dissipation would be much higher than the solenoid rated power and apparently it is not possible to go below 12VDC. I don't want to search for and dig out a fried solenoid.

>>2626754
24VAC is more efficient and gives you the option of adding solenoids further away from the controller without having to worry about voltage drop as much as you would with DC.

>>2626732
>You can't use a simple diode to stop the inductive spike anymore,

the inductive spike occurs coz of a sudden cut-off of power.
an ac waveform is so slow it gives the solenoid an eternity (or two) to release any magnetic energy into the source.

>>2626776
You still can get a spike on AC, if you disconnect at correct time.
This is how old fluorescent tubes drivers worked... Well, partially.
But most mechanical relays can handle this, and triac-based relays will turn off when voltage crosses zero and wont have any issues.

>>2626737
No the inductive spike from the solenoid valve. They're solenoids.

>If you want to spend more money to do the same thing, sure.
>spend more money
Do you mean the solenoid valves eat that much more current than the relay coils that the resultant transistor is more expensive than the relay? I don't understand how mechanical relays are somehow the cheap option.

>>2626742
Switching DC to them if possible, though using TRIACs might be an option, and would probably be a similar cost to using relays. If the valves are designed to only run on AC (as is likely) then why not just make the thing use DC valves in the first place? My question is more aimed at design philosophy of the original setup, not for the anon who wants to modify it.

>>2626754
>the power dissipation would be much higher
I don't understand this. Wouldn't a DC magnetic field result in a stronger pull force per rms amp of current?

>>2626776
>an ac waveform is so slow it gives the solenoid an eternity (or two) to release any magnetic energy into the source.
As the other anon says, you can disconnect it at the very peak. Arguably using discrete TRIACs and a bipolar driver instead of relays means you don't have to worry about that, which would be cheaper than a zero-crossing detection circuit.

>>2626778
>But most mechanical relays can handle this
Really? I know they're rated to break arcs to some extent, but inductive spikes hit different. I've seen mechanical switches melt from inductive spikes.

</autism>

>>2626789
>I don't understand this. Wouldn't a DC magnetic field result in a stronger pull force per rms amp of current?

AC solenoids are heavily reliant on inductance to provide impedance. They have much less impedance to DC than solenoid coils made specifically for DC. The latter use thinner windings to keep DC current in check via resistance. Running an AC solenoid on an equivalent DC voltage will allow much more than the designed current through it, causing excessive heating of the coil

>>2625062
>>2626733
>>2626741
Here's something that might be relevant to your interests: https://www.youtube.com/watch?v=6bqBsHSwPgw
TL;DW: Bong makes fake sun with convincing light columniation using repurposed satellite dish.

>>2626795
Did you read the part where I wrote
>a stronger pull force per rms amp of current
?
When you're designing a solenoid valve or relay, you don't design it for a certain inductance, you design it for a certain force output. Because force is what matters for switching contacts or moving valve shuttles. And force is proportional to magnetic field strength, which is proportional to current. But an AC solenoid will have more dead-time and hysteresis, so for the same rms current you'd get less average force. Heating is proportional to rms current, hence why I chose rms current as a metric in the first place.

I took it as a given that an AC solenoid will eat more amps when run on the same voltage DC, because the post I was responding to was already talking about how people hack a 24VAC solenoid to run on 12VDC. Maybe it would be better to use a lower DC voltage, or maybe a higher DC voltage, to better match the same current rating or force rating as it would see at its rated AC voltage. But why the assuredness that an AC solenoid would be running at higher power dissipation even when undervolted?

>The latter use thinner windings to keep DC current in check via resistance
That means mean that an AC solenoid would heat up less for the same rms current than a DC solenoid, regardless of whether it's having DC or AC. You need a lower voltage to get that same field strength out of DC compared to AC, because the ESR is lower than the reactance.

>>2626804
The soapy water though. Shoulda persisted with the other scattering method he was trying out.

I need a power supply that can handle spicy amps

Is the best way to just make one myself? Do I just get a chunky toroid and wire it with a potentiometer?

What is the best tutorial to build a headphone amplifier? I also would like to know how does it work.

>>2626833
>Is the best way to just make one myself?
Probably not. How many is 'spicy'?
>Do I just get a chunky toroid and wire it with a potentiometer?
No.

>>2626838
Something like 20V 20A for electroplating.
All the variable ones I found cap out at 5 amps ish

>>2626804
Now I can live in bunker

>>2626836
Check out this guy:
https://www.sound-au.com
He has a variety of audio circuits with proper descriptions of all of them. For your use case there's projects:
>24: nice looking powerful circuit with a good dose of feedback for a highly linear output, though it uses plenty of electrolytic series pass caps that I'm personally not fond of
>70: discrete transistor circuit, could be fun but I would hesitate to call it hi-fi
>109: nice low-power amplifier for sensitive headphones
>113: a simpler and still reasonably powerful power amplifier with feedback

>>2626839
20A is kinda high, I usually find 6V to be enough. Running a high surface area, low distance through fluid, high fluid conductivity, and a low voltage will ensure that you can get reasonably high currents while preventing the unwanted side reactions that happen at higher voltages (liberation of oxygen, chlorine, etc.).
But if you're plating complex parts in big tubs it's hard to get away from high voltages.

400W is in the ballpark of an ATX PSU, and is non-trivial to diy unless you're rewinding a microwave oven transformer and using a fat bank of rectifiers and capacitors, or slapping a couple of 2nd hand ATXs in series for 24V. But you probably want something with variable voltage and an adjustable constant-current mode. For which there are some high-power adjustable DC-to-DC converters you can buy for reasonably cheap off scamazon or fleabay, but their current ratings are usually based off those of the chip, not of their particular implementation, so be prepared to add a heat-sink and fan to these modules in order to get their rated power output. Pay attention to their input and output voltage ranges, and whether the output can go below and above the input, or just one or the other.

Personally I'm designing a buck-boost PSU that will run off an ATX for CC/CV in the hundreds of watts range using a pair of TL494s and some big toroidals and a bank of modern FETs. Plus linear postreg, and datalogging.

>>2626849
electrokit has a 2x 21V 7A toroid which would get me most of the way there. I'm mostly just wondering what else I need to consider so that I don't burn my house down.

I do have a spare PSU or two laying around, I s'pose I could have a look at those.

>>2626852
Problem with big mains transformers is they need big output capacitors, or else you'll get a lot of output ripple. Pulsed currents will result in a different surface finish last I heard. Which would be a neat thing to experiment with.

>>2626853
How big are we talking? I actually have some 25V 1000uF caps since a power supply repair I did earlier

>>2626853
Also on the note of a computer PSU. It seems to provide both +12 and -12 at 38A and -0.8A respectively.
You sure I wouldn't burn my house down by running the current across them?

>>2626858
>both +12 and -12 at 38A and -0.8A respectively.

fun fact: if you use 24V from +12 and -12, your current rating will be the lower of the two: 0.8A
to get 24V at high amps, you gotta use two diff supplies, and put the two +12V in series.
but gotta make sure you cut off the ground pins, and make sure the cases never touch.
or else you get a short.

not sure this link is all correct; too lazy to check, but i get the impression it is:
https://www.instructables.com/Two-ATX-PSU-One-juiced-24-V-DC-PSU/

>>2625708
>If I find an electric motor out of an old electronic device can I "reverse" it so it produces electricity, therefore allowing me to hook it up to a fan on my apartment balcony and make a mini wind-turbine.
A terribly inefficient one, yes
>Furthermore, what's stopping me from having magnets spinning around a copper spool and the copper spool then having its wire be fed out to power electronics?
Congrats on reinventing the wheel

>>2625960
>There was a thread last year I think by another anon who did something similar with a linear actuator.
Kek that was also me I just never got to making the thing.

>>2625316
I have researched a bit. There is something called a "shore scale" which is used to describe the "softness" of a material
I can buy 500g of modelling silicone with a shore rating of 5 (as soft as gumi bears). I think I know enough CAD to design a positive mould and get it 3D printed
This project is quite mechanical design intensive just as you predicted

>>2626889
>gummi bears
seems like it would tear. I would determine the shore rating of commercially available solutions and match that

>>2626517
Watch this video before you do it.
https://www.youtube.com/watch?v=FBeSKL9zVro

>>2626795
>>2626805
The problem with running an AC solenoid with DC is AC solenoids require a higher inrush current to open it and then a lower steady state hold current. For DC they will be both the same. That's why I guess converting 24VAC to 12VDC is a compromise that gives you enough current to open it but it is still a higher than rated steady state current.

>Did you read the part where I wrote
Not him, but another way to put it: you need to make sure not to exceed I^2R. Since DC resistance will be much lower, you need to lower the voltage to keep the rms current approximately the same. But like I said, it has to be higher than rated otherwise your AC solenoid will not open.

>>2626757
Sure, and I don't understand the obsession of some people on the web about powering a 24VAC valve with DC. I don't understand their "use case". Perhaps 12VDC is easier to obtain than 24VAC if you are building a sprinkler system from scratch (yikes) but have to use AC valves, perhaps because they are more common.

>>2626986
>I don't understand the obsession of some people on the web about powering a 24VAC valve with DC.
I'm guessing it's because laymen get freaked out when they hear "AC" so they default to what they feel comfortable with. lmao

Are there semiconductors with low temperature coefficients?
The +3300 ppm/C drift of silicon is a persistent barrier for analog log/exp converters, you'd think an academic lab somewhere would have something better

Where do i find good equipment? Every scope from the 80s and 90s still goes for $300.

>>2626698
>4 layer
>drive LED
Uh. Are you dumb? You can route it on one layer. Just as compact.

>>2624853
Is this AND gate design legit? When I tried to recreate it, the current on second base just passed onto emitter and the whole output worked independently of first input. Could it be because my base voltage/current is too high?

>>2627089
Seems legit.
Note that “1” is going to be anything above .7 v.
“0” should be tied to ground or lower.

>>2627032
Usually you heat-couple another semiconductor, like a diode, to the one you want to compensate, and put it in a position so that it’s tempco counter-acts the other one.

Diode Gone Wild just did a whole video on this with his 5v power supply.

>>2626889
Are you sure? I remember seeing a photo of what looked like the base of a fleshlight at the end of a linear actuator.

>>2627137
>Are you sure? I remember seeing a photo of what looked like the base of a fleshlight at the end of a linear actuator.
Then it must've been a different anon. Absolutely wild to me that someone else is doing something similar

Is there such a thing that works like a potentiometer, but you can set it with a voltage/amperage and it will retain its set resistance after power is removed from the setting terminal?

>>2627032
Ovenise everything. If you use peltiers then you can set the temperature to something more reasonable.
Tempco matching of discrete semiconductors falls under the umbrella I like to call “analogue arcanery”, and is something you’d have to study without the help of simulators or anyone who isn’t a wizard. That said, pairing both ovenisation and tempco matching is the only real way to achieve instrumentation-tier stability.

>>2627089
Need a larger value base resistor, smaller value pull-down resistor. A factor of 50 between them should suffice. Though using logic level MOSFETs will sideskirt that issue.

>>2627208
There are digital potentiometers, which have their own non-volatile memory, but watch their input voltage range. They can be controlled by pulses generated by an analogue circuit, but it’s usually best to just use a microcontroller. Which itself has non-volatile memory anyhow. So you could use a microcontroller in conjunction with any old controllable impedance, like a JFET, H11-styled photoFET, or vactrol. Even that one strange unbuffered tri CMOS inverter, or an operational transconductance amplifier, could work. These would all require a DAC (or filtered PWM), at which point I think you’re better off re-evaluating your circuit to just use a DAC instead of a potentiometer. A programable gain amplifier is the other option, needing an MCU but not a DAC.

>>2627208
>works like a potentiometer, but you can set it with a voltage

a motorized volume pot.
i pull mine from old stereo equipment.

>>2627041
I got my Tek 2232 from ebay for $150 shipped, but that was in the before time. Shipping companies are throwing out "fuck you" numbers now for anything that weighs more than a few pounds. And that's in addition to the inflation on the goods themselves.

I'm reverse engineering a flash lamp circuit and so far i was able to get this diagram of it. Voltage at the capacitor is 325V, i was wondering what the turn ratios of T1 and T2 could be.
Anyway is there some website or video that explains this type of circuit in detail? I've also seen it in other flash lamps I've disassembled.

>>2627242
Honestly, this is fucking brilliant.
I’ve often wanted to put a servo on, say, a multi-turn wire-wound pot but never had the guts to do it.

>>2627256
That one on the right looks like it might be a Hartley oscillator. There is much written about that.
The thing on the right is a big-ass inductor, when it gets charged up the field will collapse and it will generate a monstrous voltage to ionize the xenon gas for a millisecond.

>>2627256
That one on the left looks like it might be a Hartley oscillator. There is much written about that.
The thing on the right is a big-ass inductor, when it gets charged up the field will collapse and it will generate a monstrous voltage to ionize the xenon gas for a millisecond.

>>2627242
You can just buy these? I want to use these for the CC and CV feedback loops of my benchtop PSU.

>>2627104
>Diode Gone Wild just did a whole video on this with his 5v power supply
Aha, he's the electronics ESL youtuber with the most unbearable voice I was looking for a month or two ago.
His temperature compensation method is about as brute force as it gets, and doesn't really go into the mathematics behind it, let alone how you'd tune it better. I'm also not fond of his circuit design methodology, because I have an affinity towards op-amps and detest the LM317.

>>2627291
>Hartley oscillator
I know that it uses the transformer coils to open and close Q1 at around 10kHz which causes current to flow between pins 3 - 5 of T1 which induces current in the secondary coil which is cut off to only the negative half of the sinewave.
I don't really care about anything to the right of C2 since I want to repurpose this circuit to charge capacitors.
I'd like to modify it so it can be powered with a different battery like a 18650 or a 9V and to limit it's output to something like 200V.
I assume to do that I'd need to make the turn ratio between primary and secondary be something like input voltage:output*2 and then the center tap would need to be enough to actuate the base of Q1?

>>2627256
Is that drawn wrong? Looks like there's a constant current path through BT1 and T1's pins 3 and 4 while the switch SW1 is turned on. Holding down the switch would just burn something out.

>>2627354
For voltage limiting, use a zener + optocoupler circuit. That addition alone is probably enough to get it to run off an 18650.

The turns ratio of a boost-style circuit is the ratio between the peak voltage on the primary and the peak voltage on the secondary. Q1 will see a voltage spike on its collector when it turns off, which will be translated to a spike on the secondary that gets rectified and filtered into the capacitor being charged.

Honestly I think it would be easier to just use that transformer (or another one) and make a conventional boost or flyback converter. If the transformer you use lacks an air gap, you'll need to either make one, or add some series inductance instead (idk if this works). A forward converter is also an option, both are doable using a TL494 and a simple gate drive circuit.

>>2627354
>I'd need to make the turn ratio between primary and secondary be something like

all that complex calculating shit is gonna give your pretty lil head an ache.
i just get these disposable film cameras for $1 from the thrift store, pull the PCB, and cut off the excess circuitry.
an obsolete point-and-shoot film camera would work as well, just a lil more work to extract.

goddam ebay sellers
bought a variac and it gets damaged in shipping since he mostly padded the sides and top but not the bottom and UPS slammed that shit and the fuse holder in it has the wrong cap so I doesn't even reach far enough to connect with the contacts. Probably just gonna gut it out of the case and put it in a tesla coil control briefcase. At least its a nice used staco.

>>2626680
Get a couple of different brands of breadboard and a grab-bag of components from suppliers of your choice. You can use a USB charger for a power supply until you step up to higher power circuits. A multimeter is required, but it doesn't have to be expensive. Start out with simple audio circuits as they are relatively simple to understand and build.

>>2624853
r8 my coilgun.
I built it to mount it on a model ship and shoot the ship of my brother. Both are plated with 2mm balsa to allow for us to sink each other.

All electronics are analog. I thought Microcontrollers would have been too slow.

>>2627437
>You'll shoot your eye out.
Pretty cool. I want to see a real-life scale model naval battle controlled by adversarial AI.

>>2627227
>There are digital potentiometers, which have their own non-volatile memory, but watch their input voltage...
Thank you for your reply anon. Unfortunately, if the whole thing isn't analogue, it kind of defeats the purpose. I'm thinking that what I'm looking for probably doesn't exist. If I could use something like an op-amp or a vacuum tube, combined with a sufficiently sized capacitor, it would be close to working (but not at the accuracy that I need). I only need it to retain its resistance level for a couple of seconds.
>>2627242
>a motorized volume pot.
Thank you anon. I thought about something like this, but unfortunately, that's gonna be way too large for what I need. I also thought about making a magnetic actuator that slides a contact across a strip of carbon or something like that, but I think even that would be too large.

Just so you guys don't have to ask, I'm trying to make a physical edge detection algorithm for a small image. Basically, you would draw a picture on a transparent medium. Shine light through the medium onto a grid of photo resistors, then run an image manipulation kernel over the outputs of the photo resistors that will set the [magic component]s on another grid which are attached to LEDs that will show the altered image.

>>2627446
>Just so you guys don't have to ask
I don't understand.
https://en.wikipedia.org/wiki/Punched_card_input/output

>>2627446
>which are attached to LEDs that will show the altered image.
I thought the brightness of LEDs was not proportional to their input voltage? Isn't there a better way to do this?

>>2627440
Saftey glasses are enough to stop the steel from hurting my eyes.
I will report back once we have our first battle under the belt.

>>2627437
Stats? What's the mass and velocity of the projectile? How do you power it?

>>2627458
Velocity
>Hurts pretty bad when I hold my hand in front of it.
Mass:
>8.8g hardned steel projectile 6x14mm
Power Supply:
>12s Lipo batterypack from my electric longboard.

I still need to build a chronograph to get more precise data about velocity and muzzle energy.

I have made my own PCBs to control the coil.

>>2627227
>Tempco matching of discrete semiconductors falls under the umbrella I like to call “analogue arcanery”
it's not that hard desu, just calculate endpoints and assume linearity in between. I'd say ovens are more obscure.
What's your go-to oven build?

I wonder if 3d printers can be used in etching copper pcbs, instead of a 2d one. Print a thin layer of PLA to cover copper areas you want to keep, and then etch as usual. As long as the plastic does not produce mustard gas, it should be fine right?

>>2627437
your coil gun is too little man.
How about you use an SCR and big ass capacitor, like 2000 joules of energy in caps.

>>2625548
Stop being a bitch. Also, lead free solder fumes are kinda more toxic, as temperature is higher, so i hope you have fume extractor.

But yeah, lead free sucks to use, i soldered last project using lead free, and i had to crank my 936 knock off to maximum temperature. So maybe you want T12 or any modern station

>>2625548
Just nib some lead solder wire from time to time and to immunity

>>2627543
What is the point in making it bigger?
Increasing the size just for the sake of it is american retardedness for that I am too eurpoean to understand.

Charging caps takes way too long. I want this thing to be able to fire at least 60 rounds per minute or more.
This thing will be mounted on a 1.4m long RC ship and only ever has to penetrate 2mm balsa wood.

>>2627446
So basically you need to store a bunch of analogue voltages for a few seconds? A sample+hold circuit is the only way I can think of. If you use decent capacitors and FET-input op-amps like TL074s then it should work fine. Calculate the leakage rates for the required specs of the analog switch.

>>2627521
Doesn't stick well enough, but it could work as a photomask. I just bolted a 5W laser to mine to burn away black spray lacquer that acts as an etch resist.

>>2627575
I see, you don't want to have protection when Ahmet comes to rape you in the house

>>2623644
Continuing from this, dug deeper in BoardViewer and figured out the GFX_CPU signal with 1.8v was due to a faulty comparator/digital converter messing something up (after watching a few yt vids with boards having a similar issue, one of them featuring the same board even), supposedly the buck converter should still work upon removing the aforementioned and step down the 12v line to ~1v due to some bs feedback which I assumed would work on mine, but it actually doesn't so I guess it's something in the buck converter itself and not one of the controllers; I think the driver mosfet isn't getting the proper signal from the PWM controller, maybe and I can't test it due to time and life constraints.
Anyway I think the 1.8v signal on my current test CPU was a bit too much and it might've killed it, but I'm not too sure; shit does get REALLY hot, enough to make a blister on my fingertip.

Not sure if this thing is worth fixing, I've got another board of the same brand and model which previously had all proper CPU voltages but wouldn't recognize any CPU; but I fucked something up on that one, think it's a driver mosfet controlling GFX_CPU which I was going to use as a spare for the other board lmao. Shit's cursed, I was testing the voltages on that one and since it's very tiny one of the gates (PHASE5 driving GFX_CPU) got shorted to ground...

Still have no idea what I'm doing.

>>2627609
> analog switch
Hand-waving a mythical part into existence, are you talking about the cmos 4016?

>>2627452
Not sure, but even if it's not proportional, I can correct for that somehow. I just need the missing magic component.

>>2627609
>So basically you need to store a bunch of analogue voltages for a few seconds? A sample+hold circuit is the only way I can think of. If you use decent capacitors and FET-input op-amps like TL074s then it should work fine. Calculate the leakage rates for the required specs of the analog switch.
Thank you, anon. I will look into this.

i injured both my hands at my previous job. still hoping for a $100k payout. anyway it was a double thumb injury, pushing my thumb and index together for example is very painful.

this makes using tweezers and holding a soldering iron the conventional way painful. has anyone ever experienced a similar issue (technically i at least have basal joint arthritis in both joints). will I be able to do what I love any more without it causing me mass amounts of pain?

Ive spent most of my career as an electronics repair tech where I did frequent PCB repair. And most of my hobbies involve assembling small electro-mechanical devices.

please tell me I can do these things again. is there a surgery? will painkillers work? are there tools with ergonomics for differently-able'd people like myself?

>>2627813
Sorry, anon, I can't answer your questions, but regarding holding the soldering iron you could do it this way >>2625411
I don't mean exactly lol, but notice how you could avoid pushing your thumb against your index finger, some people hold a pen in many different weird ways. You could try holding tweezers this way, too.

>>2627756
Not quite. Something more like a DG4xx series, see my spreadsheet: >>2619327

>>2627813
Considering what that guy with leukaemia is doing with mechanised prosthetics, pretty sure there’s an option. I’d look into making a moulded silicone piece that straps into the crook of your thumb, with tools like soldering irons able to strap or bolt into that piece. Probably needs a solid internal frame for rigidity. Then I’d add a solid lever that your fingers can hold to provide to provide some control over the tool.

>>2627823
lawful good is how i used to write and solder. ive been having to write now after the injury as neutral evil.
lawful evil and maybe neutral good look doable.
really trying to avoid chaotic evil

actually i was true neutral i think for writing. sorry to waste a post for this

>>2627829
> what analogue switch?
> see spreadsheet
You certainly bitchslapped that question out of the park without even using your strong pimphand.

Can I get a recommendation for a high quality DC 12V to 5V converter? want about 30A capacity, it can be broken into a few smaller units. Its for using new ATX PSUs in older computers; the capacity of 12V on ATX PSUs is massive, many multiples what is needed for older computers. but the capacity of 5V is a lot less, about 30A less on one particular unit. So figured I'd use some of that 12V capacity to turn it into 5V. But I want the 5V output quality to match or exceed the original high quality power supply.

I'd actually prefer linear, but size and heat is a concern (efficiency is not), so think it might have to be switched mode, but not sure. Ive always focused on linear supplies so Im not sure what makes a good switched mode. I am guessing stability, and switching frequency. Do you think I'd have to worry about the switching frequency being less than the old 90s power supply?

If I decide to feed this 5V into the mainboard, it is very important that the antique board not be damaged by a shitty power supply.

>>2627917
What is this “antique” board that requires 30A?
It would have to be a discrete TTL cpu.
There was only one PC-class thing with a linear power supply that I’m aware of.

>>2627917

there's something called amazon you can search.
i always thought it was a river in the country of Africa, but apparently it also sells things.
and it uses stars as a kind of ratings system, so why know what's good or less good.

>>2627917
Hello sir, would you like to hear about the gospel of the TL494, with FET gate drive circuit and hand-wound toroids?

>>2627926
Did you try reading beyond my first sentence dipshit?
>I want the 5V output quality to match or exceed the original high quality power supply.
> Im not sure what makes a good switched mode. I am guessing stability, and switching frequency.
>Do you think I'd have to worry about the switching frequency being less than the old 90s power supply?
>it is very important that the antique board not be damaged by a shitty power supply.
and actually even in my first sentence:
>Can I get a recommendation for a high quality

>>2627923
Power Mac 9600. The stock PSU has like two 5V rails totaling 48A. Modern ATX PSUs typically only do 20A on the 5V rail, even the high wattage ones. So I just want to compensate for that 28A difference.
The 9600 PSU only did 11A on the 12V rail, where modern ATX supplies do like 60+A

The stock 9600 PSU is also the size of like 2.5 ATX supplies. So, I basically have room for an entire other PSU, but I want to not add more than like an additional half ATX supplies worth of volume on top of the ATX.

Will that $30 Amazon piece of shit the other anon posted work?

>>2627931
SMPS down to 7V and use 30x 7805 regulators?
I wouldn't exactly trust amazon SMPSs out of the box. Partially for noise, but mainly because they're just not built to the same standard as an ATX with all its safety interlocks. For protecting both the computer and your house. Either look for a well-documented existing DC-to-DC solution from Meanwell or on Digi-Key, or make one that you'll know to have sufficient specs and safety features.

I like the look of this thing:
https://daygreen.com/collections/12-24v-to-5v/products/12v-24v-to-5v-50a-250w-dc-dc-step-down-converter-voltage-regulator
It looks like it has multiple inputs and outputs, which is exactly what I would want. unfortunately the shitty datasheet doesnt show this; pic attached

>>2627929
I sure would

>>2627938
>shenzhen
I'd sooner buy 3x 50W Meanwell converters, or whatever. If only they had an SD150A-5 (only the A series can go down to 12V input), but they only have SD100A-5 or smaller (SD100 = 100W). Pic related is from here:
>https://www.meanwellusa.com/upload/pdf/SD-50/SD-50-spec.pdf
Compare those EMI standards to what an ATX has, and to your Shenzhen jobbie if you want. You can always add extra filtration.

>I sure would
Ok well take this with a grain of salt because I've been shilling this chip for a while now.
A TL494 combined with a FET gate driver is a simple but very versatile method of making a reasonably modern SMPS. It lacks current-mode or PPM switching, and won't do ZVS or ZCS or other resonant/quasi-resonant topologies, and its quiescent current is kinda shit, but it's perfectly capable of shitting out a few hundred watts at a fixed frequency. Which is easier to filter out anyhow. In this case you don't need isolation, so a simple synchronous buck topology would be the way to go. Just add a pull-down resistor to the output emitters, and feed that into a half-bridge driver, which controls a pair of good FETs, all running on 12V. You can even have multiple drivers and FET pairs, though it can't do multi-phase conversion. I'd probably use a more reliable external voltage reference than the internal one, maybe an extra PSU overseeing IC for fault detection, and the output filtration can be whatever makes most sense for you. A CLC pi filter may be usable if the resonant frequency is matched to the oscillation frequency of the switcher, but with variable current draw you'll need to ensure that the inductance doesn't give you spikes. Chokes should work, so should inductors with shorted second windings, maybe? You can even add linear post-regulation in the form of beefy capacitance multipliers, just take the feedback path from after them. I'd tune the feedback loops to have a bit of P and I as well as D. Use the second for current or temp limiting.

>>2627949
oh and by pull-down i mean an inverted version of this: https://www.circuitden.com/blog/11

please hire me
i'm begging

This dimmer switch started to cause random flickering. Is the transistors the weakest link here?

While we're talking about regulators is it worthwhile to put an inductor on the output of a linear regulator for filtering? I'm redesigning someone's board and they put an inductor on the output of one linear regulator even though the datasheet doesn't recommend one and I've only seen it done with switching regulators.

>>2628069
Clean the contacts with a pencil eraser or contact cleaner.

>>2628069
I'd check the pots first personally.

Have crates of this old capacitors which were all pulled recently from working environment.
So I have this small aliexpress tester and for example with this one I have drift from 8uF to 10uF.
I know this tester is kinda precise with lower voltage caps but I'm not sure how well it works with 250v ones or it doesn't really matter? Any info on that?

>>2628108
This is test result tho with shitty leads, with soldered ones it's 10uF and 1.3Vloss.
Also if anyone knows, when those meters don't display ESR is it actually really low or what? I know that with some caps it does display ESR but not with these old metal can ones.

>>2627365
>Looks like there's a constant current path through BT1 and T1's pins 3 and 4 while the switch SW1 is turned on.
You're right here's a fixed version

>Honestly I think it would be easier to just use that transformer (or another one) and make a conventional boost or flyback converter.
So just get a transformer with 9:400 turns (for a 9v battery, and 200v output after rectification) switch current through it with a mosfet or bjt driven by a 555 timer at a few kHz and rectify the output of the secondary with a diode? Would that work?

>>2627367
I already have this circuit, I took apart a camera flash I want to adapt it to suit my needs better and understand how it works.

>>2624853
I'm trying to build a XOR gate. As far as I understand this doesn't work, because signal from switch 2 always shorts on Q1, and thus it never passes through the diode. I tried adding some resistors/diodes/transistors in the way of Q1 to make the diode path more attractive, but it just tips the balance the other way and the diode doesn't go off then both switches are on.

How do I fix this? What do I fail to understand here?

BTW I use resistors only between the source and switches, I tried placing them here and there but it doesn't seem to make a lot of difference (diode is safe btw)

I got one of these for free. Should I keep it? What should I use it for? Would it be good for testing RC motors?

I would 100% keep it but I have an irrational dislike of HP. I suppose I could look for an Agilent badge to put over HP.

Also it seems to be worth a lot of money so not sure if I should sell it and maybe buy a cheaper high resistance meter.

>>2628194
Pretty cool. I have a 60s HP rf generator myself I should probably sell. Thing is like 4 rack units and all tubes. Just sits in storage.

>>2624853
i bought some 0606 RGB LEDs without realizing how fucking tiny these are. how exactly do you solder these without bridging the 3x2 pins?

>>2628248
Drag soldering.

>>2628248
more flux

>>2628135
A few caveats. Firstly, your peak primary voltage will be higher than 9V since it spikes whenever you turn the FET off. Secondly, any old transformer won’t work, it needs to have an air-gap for some arcane reason. Thirdly you probably want some feedback, otherwise the voltage at primary and secondary will keep rising until it damages something. Monitoring peak primary voltage is what I’d do, run it into a peak detector (diode plus capacitor) and feed that into a comparator that turns off the 555 when some voltage is exceeded.

>>2628156
So if Q1 and Q2 are both turned on you short V2 to ground? Don’t you need a collector resistor? Also if Q1 is off but Q2 is on, you’ll get current flowing from base to collector. So put a diode on Q2’s collector. Or use small-signal MOSFETs instead.

>>2628248
Paste, hot plate, fine tweezers, and lots of flux.

where should I look for theory about improving amp linearity with feedback?

>>2628084
the inductors on smps are not for filtering. its part of the converter topology that allows for the step up/down features. if you want filtering, use a bulk electrolytic cap and a few ceramics. if youre really in the market for inductors for filtering a power supply, youd be looking more at a ferrite bead, even then, they work differently than simply caps or inductors

>>2628194
>Would it be good for testing RC motors?

it's a special purpose instrument to read resistances/impedances between 500K and 2x10^16
it can put out 1000's of volts, so it's not a toy for noobs.
could be a useful gift to someone you dislike a lot.

>>2628295
I used something like this at work routinely, but that was called an insulation resistance meter. I think its the same thing but maybe not. We used it for testing motor windings. I also never saw what happened for a catastrophic fail. I always hoped it would like detect it and stop pumping 500V to it.

Thats why I was wondering if itd be good for RC motors. Fun fact while using the one at work some noob engineer who was acting like my boss was mad at me for not multitasking while doing insulation testing (the tests are 60s). Like dude fuck off, trying to save 15 minutes to risk me either possibly dying or hooking it up wrong and destroying the $80,000 motor we spent months building.

no wonder that place fucking injured me.

>>2628248
spot weld

>>2628248
IR laser

>>2628311
*the tests are 60s with 12 different locations done per motor. so about a 15m job total.

absolute cheapest possible way to build an (safe) 18650 cell charger? bonus points if i can source all the parts at microcenter.

>>2624853
>>2624853
>>Li+/LiPo batteries required reading:
>https://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf

dead link

>>2628316
>absolute cheapest possible way to build an (safe) 18650 cell charger?

dollar store power bank.
you get not only a (super duper quality) charger, but a free lipo.

>>2628321
lol i appreciate that suggestion, but I already have the lipo, it was gifted to me!

>>2628317
o shit
taking recommendations for a replacement document, i'll see what i can find before next thread

>>2628363
>https://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf

https://web.archive.org/web/20230403213449/http://www.elteconline.com/download/pdf/SAFT-RIC-LI-ION-Safety-Recommendations.pdf

Just thought I'd post this here:
http://dangerousprototypes.com/forum/index.php?topic=7218.0
It's a high-power soldering station circuit that can be adapted to basically any soldering handle you can think of, double-tipped tweezers included. Which has inspired me back to designing the XT60-powered portable iron "Ohmcil".

>>2628398
Found the updated version somewhere else:
https://buster-spb.ru/files/SAFT/li-ion_user_manua.pdf
Key was searching for:
>"saft" A0018-10

>>2628411
>"Ohmcil"
Nice. I hope it turns out well because I'm sick of seeing retards get ripped off with that pinecil bullshit.
>Key was searching for:
>"saft" A0018-10
Just wanted to post the archive so somebody could upload the pdf to mega or jewgle docs if they felt like it.

>>2628412
Well I can *almost* get it routed on just a single side using chunky traces and chunky components (MELFs included!). I'll give it a more serious shot later, but I'd still like to make the parts and assembly as accessible as possible. If not sharpie etching accessible. Maybe this galvanically isolated 14A gate driver (1ED3123MC) is a tad obscure...

The idea is to use 100V capable parts and a JBC T245 (probably) tip geometry, so you're free to overvolt it with whatever battery or PSU you care to try Maybe even 350VDC capable for the madmen who'd shove rectified mains into their tip, a 16-bit timer should be precise enough for that but the thermocouple sure as hell won't respond in time if you're hitting 100% duty-cycle. Still haven't worked out the DC-to-DC conversion, unless my 5V zener to protect the MCU counts.

Any recommendations for microcontrollers? I'm currently planning on using a UPDI-based ATtiny so you can spit one-wire down the XT60 with just a level-shifting FET, but I'll change my mind if there's a better idea. I'd rather shove both programming and power down an 8P8C than use USB for anything here.

>Just wanted to post the archive so somebody could upload the pdf to mega or jewgle docs if they felt like it.
I actually expected there to be a source on the Saft website, but surprisingly not. I guess archiving is actually a good idea. I'll keep it on my hard drive if nothing else, alongside the rest of my datasheets.

Hi, I'm looking for a fast ADC for checkweighing applications, I found this one, but it says it can make up to 153.6 (kilo?) samples per second. This can't be right, ¿right? The top end devices I've seen are barely able of doing 5000 samples per second, so it doesn't seems feasible.

https://www.microchip.com/en-us/development-tool/ARD00906#

Can someone recommend me an ADC that can perform at least 2000 samples per second? Specially if there are evaluation boards for it, since I'm not specially good at analog amplifier design.

guys do you know what the fuck are these for? flashlight?

>>2628424
Maybe a tripod-mounted work light? Post a better pic.

>>2628418
out of curiosity why are you building a checkweigher? If you're still around Thursday I can get you some pictures from inside some industrial checkweighers.

>>2628424
T10 led replacement bulbs. Those are for cars.

>>2628429
>out of curiosity why are you building a checkweigher?
I've become fairly interested in high speed weighing since I'm doing some work related to that. I feel like commercial solutions are way overpriced and I was wondering how easy would it be to /diy/ a fast and reliable amp + ADC combination for weighing applications.
Of course I'd also have to slap a microcontroller in there to do some post-processing and also some hardware to enable communications with other devices like PLCs.
>If you're still around Thursday I can get you some pictures from inside some industrial checkweighers.
That'd be neat, thanks!

I'm trying to monitor evolves and links between radon and EMI. So, in terms of sensors and metering, I'd like to monitor Radon presence.
Is there any sensors you could recommend me ?

not sure if best place to ask. What are some electronic devices which the world has enough of that a full time job exists to repair them.

Ive done cameras for 10 years. Its fun as fuck. sitting at your own desk taking apart electronics all day long every day. Just wondering if theres something other than cameras out there.

looking for something equal to or more complex than cameras. so dont wanna do like cell phones or tablets.

>>2628631
vidya game controllers

They suffer from "stick drift" because they use analog pots which can be modified to use Hall-effect sensors to correct the problem. Ben Heck covered it here: https://www.youtube.com/watch?v=HBcHfwVt82I

>>2628418
There are ADCs out there that sample at billions of times per second, they still use ADCs inside 10GSa/s digital oscilloscopes.

If you want to avoid analog design, go for a delta-sigma ADC, they naturally need much less input filtration if my understanding is correct. Delta sigmas usually have a lower sample rate but high resolution, but they still go up to 100kSa/s pretty commonly and cheaply in the form of I2S audio ADCs. Which might work fine for you, if you can find one with the right input topology (e.g. differential) and so long as they have the required power supply topology (probably seperate analogue and digital power domains). That said, there definitely are instrumentation oriented delta-sigma ADCs out there for you to try your hand at.

>>2628424
Probably T10 as the other anon says, but it's possible they're meant to fit in a USB slot instead. Depends on whether how big they are.

>>2628579
Some of these look easily constructible yourself:
https://inis.iaea.org/collection/NCLCollectionStore/_Public/36/010/36010924.pdf

>>2628631
>dont wanna do like cell phones or tablets
Those are a lot more complex than cameras, if you're doing component-level repair. How's your microsoldering?
HiFi gear is what I'd aim for. Maybe stage gear.

test

>>2628637
>Ben Heck

>>2628674
What's the problem with Ben?

>>2628646
>Those are a lot more complex than cameras,
Well, I want devices with lots of PCBs. I'm really in it because I like looking at PCBs. I also like lots of wires. Lots of connectors.

>How's your microsoldering?
It was spectacular until an injury I got 2 years ago. Now Im not so sure. Maybe I can get a painkiller prescription.

>HiFi gear is what I'd aim for. Maybe stage gear.
Good suggestion, I'll look into it. Rack equipment in general seems like a good way to go.

I guess electronic test equipment would be another good one.

>>2628553
NP, my entire job is industrial equipment. It's no big deal. I just work weekends though.

>>2628691
>electronic test equipment
Those need calibration though, chances are anyone who owns that kind of test equipment will either be sending them away each year, or getting someone in to calibrate them. Don't think there's much room in there for someone who can repair but not calibrate. If you want to spend thousands of dollars on quality references though, be my guest.

The other option is to buy faulty equipment and sell after fixing. Electronic test equipment is probably a bad market for this since the kind of people who'd consider buying 2nd hand test equipment are also the kind of people with the knowledge and enthusiasm to fix that kind of equipment themselves. But for hifi and synth racks and stuff, definitely.

>>2628695
>Those need calibration though, chances are anyone who owns that kind of test equipment will either be sending them away each year, or getting someone in to calibrate them. Don't think there's much room in there for someone who can repair but not calibrate.

Why wouldn't I be able to calibrate? I can work for the manufacturer. Ive worked for Canon and Sony. No reason I cant work for Tektronix or Keysight.

>>2624857
Author of ^
Have gotten a roll of SAC305 analogue. Notice the soldering iron temperature had to be turned up 20C, and I nearly destroyed a toggle switch soldering some leads to it. Flows ok once the heat is there, looks nice and silvery. Definitely 10-20% "slower" (to wet, wick) than lead based stuff, but seems ok. Gotta look out for plastic switches though, turns out they need to go on the list of "heat sensitive components". Just made this Orange Pi Zero board with Aliexpress li-on UPS

>>2628771
FYI pulling the enable pin low will disable the buck output.

>>2628778
It's funny you said that, I was looking at the board wondering what those two unsoldered positions were, was nearly going to ask here in case someone knew. Measured the voltage across them, 4V, current when shorted 6mA, thought maybe it was a header for another indicator LED. Tried shorting them thinking maybe that'd turn the board off but it didn't seem to, which one is the enable pin, the left one or the right one?

>>2728768

>>2628781
err wrong post number >>2628768

>>2628781
Short them together. The LED on the buck converter will stay lit, but the output should be 0V. Which version is it, XL4015?

>>2628783
Yup, I'll have another play with it

>>2627936
>>2627949
the Meanwell SD is looking pretty good, thats for that suggestion. Any opinion on their RSD series? Theyre designed for railways or any other harsh environment, so thats nice. Theyre also quite a bit smaller than the equivalent wattage SD series, which is why I am thinking going with RSD

>>2628500
>>2628646
alright. yeah seems to be that, i got them by error from ali. bought some $0.5 shit and got 4 of those

>>2628804
>Any opinion on their RSD series
Probably great. Probably expensive.

>>2628814
Theyre about the same price. I am having trouble figuring out what the catch is.

>>2628816
Huh. Are their noise or accuracy specs the same?

>>2628821
noise and accuracy is the same.
RSD has a higher switching frequency (130KHz vs 83KHz).
RSD has higher efficiency (87% vs 70%).

Main difference I found is protection mode
RSD has "Constant current limiting, recovers automatically after fault" and "Shut down o/p voltage, re-power on to recover.
SD has "Hiccup mode, recovers automatically after fault condition is removed" for both overload and overvoltage.

RSD is seeming like the way to go.

>>2628646
Yeah, all the equipment I've seen uses delta-sigma ADCs. I'll do some reserach to pick an IC that has nice specs (at least 2000 samples per second) and doesn't costs 20$ a piece.
>>2628694
>only work weekends tho
That sounds nice. Industrial automation is also my field, if you want you can come join the PLC discord.
https://discord.gg/A9Ty8w5

>>2628646
>https://inis.iaea.org/collection/NCLCollectionStore/_Public/36/010/36010924.pdf
Thank you Anon

>>2627926
>i always thought it was a river in the country of Africa
Nah, the Amazon has always been in SA. You're thinking of Denial River.

Guys, i just disassembled two speakers that were embedded onto my wall, they're connected in series, this means they're not stereo right?

>>2629008
Correct. It's a single channel.

I'm kind of ashamed to admit that we don't have a proper multimeter at work.
For a tester calibration we're required to input the measured values but we need a multimeter capable and reliable enough to do it.
The requirements are 0.1V-2.0V with accuracy of 1% and 10 MegaOhm input impedance. The manual recommends Fluke 80 series.
Is Fluke the only option we have? My boss is not opposed to buying a high end meter but I'm afraid a 1000€ price tag will make him reconsider.
There's currently Fluke 115 on sale with the accessory kit for 265€ and it seems like it fits the criteria.

On another note. Is there a device to test the cable length by connecting alligator clips on both sides of a long cable and it telling you the length with a 10mm accuracy or better?

>>2629038
https://www.ebay.com/itm/292604392173?hash=item442094b2ed:g:72sAAOSwdydbIzK9&amdata=enc%3AAQAIAAAAwEZm%2FIQkAlWs1IWx7nL06V5xEhaAwtMRAW7SEu4xSgaW19hz%2BE%2BSQAhDPFLXlhicLEqGYPeQbD%2BWfIIR3p3jOvA3Ar97mnP77lHNxNRvvNVI0VyPGYX1dt7ZRbbyyjt4pZxvYL80Ls65KHHC%2BQ%2BzLaRfxC7xFxVCa1Cbeqsz5CmaVvC3Hbtrqz%2BJAD1f0aqYwJ2FcF3qhvxNwVNsYguNzxjVHHWOrWBAiQca7Cj9sfLM0f1z9FZok2%2Fhl1DNMhblNA%3D%3D%7Ctkp%3ABlBMUMqcosSTYg

>>2629042
No offense but I don't trust this chink shit with no technical document to help calibrate testing equipment at work.
Also we legally can't buy something that's not certified as the auditor is going to lock me up.

>>2629042
quit being a lazy cunt

https://www.ebay.com/itm/292604392173

>>2629042
https://www.ebay.com/itm/292604392173

ftfy faggot

>>2625068
Most of the autism around lighting is based on feelings.
It really is an autistic form of nostalgia longing for the better times that happened to use incandescent.

>>2629054
incandescent is literally 100% CRI. It is as good as light quality can get. Incandescents also dont turn full on and full off following a square wave many times a second like a lot of LEDs do.

most of the autism you are experiencing is the fact that the market is flooded with spiky spectral output, with a shitty color range, and often flicker.

Just look at 90% of the LEDs used on cars. They flicker horrendously. its annoying as fuck. LEDs also dont emit light in every direction; they have a beam pattern output. This requires reflectors and diffusers to attempt to come close to what incandescent does naturally, and they generally fail at it.

>>2629038
Maybe get a Brymen

>>2627437
it burnt down. It actually caught on fire!!

>>2627458
I have some numbers for ya.

>>2629079
You're not getting the context of my post.
This anon >>2625062 knows the LEDs he has are basically just as good as incandescents in CRI but yet freely admits his feelings might get in the way of his judgement and the post I was responding to >>2625068 doesn't quite get how feelings can come in because CRI is an objective measure

My post was just laying out that most light autism has nothing to do with objective measures even if they say so. You can have a perfect LED but it doesn't matter to some of these people as it's not really about measurements.

/ohm/ please help, I bought this house and the owners uninstalled their ceiling fans before leaving. I walked in to this. Why are these three wires fused together?

>>2629079
>Just look at 90% of the LEDs used on cars. They flicker horrendously
You're a fucking idiot. There's no flicker in car LEDs unless you installed some aftermarket LEDs in a car from 2 decades ago.
It is the AC powered LEDs that give tons of flicker because chang can't afford 2 caps in his 1$ bulbs so the lights dance to the 60Hz of the mains sine wave.

>>2629104
wrong dipshit. the stock rear lights on most brand new cars flicker. its very easy to see this unless you have degenerate vision

>>2629103
Pic related

Guys, how can i test continuity over long distances? I got a cable that goes through my walls and i need to know where it goes, it just a bare cable of 12V.

>>2629104
Meds, schizo

>>2629108
Who the fuck knows? If I had to guess I'd say it's the neutral lines, but they're brown.

>>2629115
Get in your attic and look.

>>2629118
I don't have an attic, i live in an apartment.

>>2629104
>car alternators put out 60Hz mains

>>2629119
You said you bought a house, liar.

>>2629130
That was the guy above

>>2629131
Oops, please forgive my clinical retardation.

>>2629119
Do you have a security system with sensors for your doors and windows? Maybe your landlord installed cameras in your toilet.

>>2629106
>battery powered LED lights flicker
Shitpost of the week

>>2629162
Take your medications, please. It's important.

>>2629125
>>2629162
i think the implication is that they're doing pwm at a low enough frequency to be visible, that or alternator ripple is somehow getting there

low frequency pwm is actually maybe a good thing, since high frequencies could alias with computer vision camera framerates and cause your self driving car to fail to see lights in some cases

or how about we just put LC filters (with a diode) after our pwming

>>2629194
>since high frequencies could alias with computer vision camera framerates and cause your self driving car to fail to see lights in some cases
Thanks for the idea, /ohm/ie.

>>2629103
>Why are these three wires fused together?

those are all neutral wires.
usu they're (superior-race) white, but age and heat has made them dark.
presumably, 2 of them go off to power some other circuit.
so just treat it as if it's 1 wire.
connect 'em to white wire of new fan/light.

>>2629115
>i need to know where it goes,

if you got $33 to burn, you can get one of these.
otherwise, just be on look-out for it.
you'll hit the jackpot someday, unexpectedly.
same way people lose their virginity.

>>2629242
>brown
>neutral
this scares me

>>2629261
>this scares me

this is the right tool for scared little girls.

>>2629194
>the implication is that they're doing pwm at a low enough frequency to be visible
They don't. They don't do PWM at all, in fact. Original retard was complaining about rear lights which have only 2 states: on or off.
PWM driven lights exist inside the vehicle where you have displays and the instrument cluster that have adjustable brightness.

>>2629162
>implying LEDs run straight off the car battery with no voltage regulation
youre not very smart

>>2629306
you are just completely wrong. Not only do rear LED lights use PWM, they usually do it at an abysmally low frequency like 200Hz. This is stock LED tail lights, not aftermarket ones.

>>2626833
>I need a power supply that can handle spicy amps
>>2626839
>Something like 20V 20A for electroplating.
One option would be to get a fixed-voltage AC-DC power supply and combine it with a variable DC-DC converter.

For example:
https://www.aliexpress.us/item/3256804906278356.html
>24V, 600W power supply - $29.12
https://www.aliexpress.us/item/3256803891622143.html
>50V, 20A variable buck converter - $54.01 (if you go for the USB+BT control modules)

>>2629306
>only 2 states

>off
>running lights
>turn signal
>braking

hmmm

>>2629306
you could have just googled it instead of proudly proclaiming something patently incorrect

>>2629350
uhh sweaty, jewgle is full of lies

>>2628783
>>2628785
No matter what I do the thing doesn't power off, shorting the two unsoldered positions, shorting either of them to ground. Maybe it's because the output is connected to a battery so it's still pulling them high

blink once if you can hear me

>>2629536

For a 2 amp nema17 stepper, which is better, A4988 or DRV8825 ?

I need to maximize holding torque.

>>2624853
Gentlemen. Does any one here know anything about magnetic transducer (ie pickup) design? I understand the formula for the inductance a coil and the model for a pickup and how it forms a second order low-pass filter etc etc. What I am unclear on is how you take a design target and turn into an appropriate object.
Say I want a pickup that is 5H with a DCR of 350Ω(this is well outside of normal pickup design targets), how do I then select the core material, wire gauge, geometry etc? Or do I take my design goals, select a core material and geometry that is likely to get me in the ballpark and then pick a wire gauge that is going to get me right at target resistance with the requisite number of wraps?
There are just many moving pieces here and I am not sure which ones to hold constant to begin.
Pic unrelated.

>>2629636
Either get a qualitative answer from /3dpg/ or get a quantitative answer by finding the maximum continuous current on their respective datasheets. Extra heat sinking may be required though.

>>2629739
Do you mean a guitar pickup? Because they typically use permanent magnets as their core.
Generally you pick a core material first for a certain sound quality (permeability is a function of frequency), then pick approximate dimensions and plug that into some equations or a good enough online calculator. Might be hard to find such a calculator with ESR and external dimensions as independent variables. If the resultant coil is impossible, too big, too strange, or otherwise suboptimal, change your initial conditions a few times. The final calculation should be done after fixing wire gauge and core diameter to values you can easily buy.

What’s the project?

>>2629083
Thanks. I needed one multimeter but now my selection is much greater so it's harder to choose.

>>2629038
I have more questions about multimeter accuracy.
The more I read the weirder it gets.
Say Fluke 87V has a ±0,05% +1 accuracy. I get the percentage but what exactly does the +1 or +2, +5 mean? Is it a fixed voltage added to the accuracy or is it added drop in accuracy of the least significant digit?
If I'm measuring 5V DC is the accuracy mentioned above ±0,0025V+1V or is it ±0,0025V+0,001V on a 4,5 digit display?

>>2629820
>but what exactly does the +1 or +2, +5 mean?

if you're reading 100.00V with a 2% error, you could get readings of 98 - 102.
if you're reading it with a 2% + 2 error, you might read 97.8 - 102.2.

>>2629822
>get readings of 98 - 102.

that should read 98.0 - 102.0
it's the last digit that changes.

>>2629822
And that scales all the way down to mV range?

>>2629816
Get the top-of-the-line EEVblog meter

>>2629827
>scales all the way down

yep, turtles all the way down.

>>2624853
Yo there, have a little problem with analog filters theory, I understand the filters can be modeled after the biquadratic equation, adjusting the coefficients, but how are supposed to approximate to a butterworth,chebyshev's or eliptic ?
What is needed to do so?
I intend to implement it with the MAX274/281-
I can make it fits more or less the design paramters but they don't have the response of these approximations.

Also
Whats a good book to learn theory and design of buck,boost and flybacks converters?
thanks a lot.

>>2629844
>modeled after the biquadratic equation

you risk spraining your brain doing that shit.
just use a filter calculator: https://webench.ti.com/filter-design-tool/

>>2629753
Yes, like a guitar pickup but I want the resonant peak to be somewhat below 100Hz. I understand that they do tend to use permanent magnets as the core (some cheap ones don't and use steel slugs with a bar magnet going bridging the slugs below) but there are many types of magnet with varying relative permeability.
Your work method sounds most reasonable to me and will probably be the path I take.
I want to make a pickup which makes cool drum sounds.

>>2629845
>you risk spraining your brain doing that shit.
Yeah, that's for sure!!!!
Thanks for the tip.

>>2629844
Ah, cool chip. Looks handy for implementing audio anti-aliasing and anti-imaging filters, though I'll have to read closer to see if its SNR is up to task.

The coarsest method would be to draw out a filter design using discrete op-amps then translate it into this lumped symbol by changing resistors while keeping their relative ratios. The actual op-amp topologies could be a simple sallen-key, or the more complicated ones shown here:
https://www.stg-maximintegrated.com/en/design/technical-documents/app-notes/1/1762.html

But it looks like there's some tidbits in the datasheet suggesting there's a simpler way of going about things. I couldn't find an appnote specifically on this IC in particular though. Looking for online calculators/tools/existing circuits may be the best way.

>>2629851
Can't you modify the resonant peak by adding inductors or capacitors?
Also guitar pickups only need a permanent magnet in order to pick up movement of ferromagnetic things. If you have something that already has a magnetic field (magnetised string, membrane, etc.) you can avoid the permanent magnet core. Furthermore, you can ditch the magnetised core and use whatever common magnetic core material you want if you just put a constant-current through your windings. This would make it easier to know what permeability you have since I doubt permanent magnets specify this, though of course you could just measure it by winding turns around different types of magnets. Could also just get away with off-the-shelf non-closed-core inductors, pic related.

It's also an option to use different types of pickups, like electrostatic (put a bias voltage between a conductive pickup area and the conductive vibrating thing like a condenser mic), which might be more suited to cases where your fingers aren't touching the vibrating thing directly. Like drums, it would be interesting to try and put a conductive membrane on a drum to this end. Another method would be a strain gauge on the string mounting or even just on the chassis of the instrument.

Also could you try putting some sort of pickup on a snare drum's chain? I think that would be cool. Not sure how you'd add a pickup to a brass instrument though, a reed might be doable so I'm waiting for an electric sax.

>>2629851
https://prosoundhq.com/alnico-2-vs-3-vs-4-vs-5-vs-8-pickup-magnets-complete-guide/

>>2629816
whatever you get make sure its on this list:
https://sigrok.org/wiki/Supported_hardware#Multimeters

>>2629855
since we touched the inductor topic. do you (or anyone) know how to measure and identify value of a nameless inductor? got one with no marks outside, just like picrel, need to buy more, but what the fuck value is it?

>>2629902
LCR meter
https://sigrok.org/wiki/DER_EE_DE-5000

I'm designing an analog vocoder for my senior design project. We're still very early in the design phase, and we breadboarded a basic bandpass filter for around 150 Hz. Both the TI filter designer and LTSpice predicted it would have a maximum gain of 0dB (desired), but when we ran a bode plotter on the breadboarded circuit, the first test (with some random off-the-shelf op-amp) had a max gain of -36dB, and the second test (with a TL084) had max gain of -18 dB. It was a 4th order butterworth MFB/delyanis-friend filter. We tried to add a gain-makeup op-amp after it (knowing it wouldn't work but Fuck It™) and it boosted the maximum gain to -12 dB, but also trashed the frequency response (the low-pass started acting like a shelf)
What would cause such a discrepancy? I assume something to do with the gain-bandwidth product, but it's not like the stages are super high gain, and the bandwidth isn't super narrow

>>2629945
>breadboard
probably has something to do with it

>>2629902
Do you have a transistor?

The easiest way to get the inductance is to put it in an oscillator circuit like the colpitts oscillator in picrel, and choose component values in the audible range and listen to it, comparing against known inductor values.

This is the way some LC meters work, except they use a frequency counter and the “range” switch is used for swapping out different capacitor values in the oscillator.

For the other values (like how much current it can take/wire gauge, core saturation, q, etc.) it’s a little more complicated but obviously we’ve got the most important one covered.

>>2629945
Build a simple first-order sallen-key (which is hard to fuck up) and run the bode against that to make sure everything is good. Use the exact same op-amp and components you used with your other filter.

Once you’ve done that, let us know. If you get bad results, make sure your probe isn’t on x10 or x100 or something and other classic blunders.

Do you have a picture of it? Unless you’ve done something crazy, 150 Hz should be doable on a bread board.

>>2629992
>doable on a bread board
Sure, if the breadboard isn't made out of Ramen noodles and industrial waste.

>>2629995
> Ramen noodels
Good point. A buddy of mine in EE spilled gatorade into his breadboard, and lo-and-behold…. it’s very conductive. Don’t eat and drink over your breadboard either.

Get a fresh bread board if you think there’s a possibility that’s happened, or you’re using “shared lab resources” where it’s possible/likely someone pissed on them. Also conductive.

>>2629975
i got many electronics. the comparison way i thought was just making a lc filter, injecting white noise, and then measuring cutoff freq and comparing with other known inductors, but i got no more of that type inductors so ig ill get an assortment.

>>2629854
Thanks for the handy information.
Thanks for your kind help!!!

I somehow managed to fry two of these when testing a piece of hardware with a bad Vcc in (dunno if i said that right). Is there any hope in repairing them, I checked all the diodes and they tested fine.

>>2630044

>>2629999
>Also conductive.
probably only if you don't hydrate yourself enough. if you drink two gallons a day, your urine will be crystal clear and probably not very conductive. i will post proper color next time i need to go, stay tuned. i will also measure conductivity. sounds like a good weekend project.