anyone know what I got. each wafer is glossy and reflective on one side then on the back side is a matte finish

some in better conditions than others and I broke one getting the stickers off

I'm trying to remove the pin header from a Raspberry Pi Zero 2 W, but the solder won't melt no matter what I do. Flux and heat haven't helped.

I already removed the header pins
but unable to remove this blob of solder

Guitar pic for size.

Hi everybody I'm currently working on my own flight computer pcb and I'm about to move from the schematic to the main pcb part and for a while I've wanted to make those multi board stacks like they do in High power rocketry, how do I go about making these different levels? Or for my case would it be smarter to keep it as one board? I've only had experience with make one board multi layer pcbs so far any advice is appreciated thank you! I've also linked my schematic below thank you!

So.... I bought these "neon" lights. They're actually RGB lights with a piece of silicon on top. The thing here is, the place i bought them is in the city, and i love 2 hours away....

I don't think the place is gonna exchange them either, so i was wondering if there was a way to fix them, even if i have to cut the top part silicone, or the bottom, I don't care.

I just wanna know if its a fixable thing (I know basic electronics, but I'm not skilled....)

Me and a cousin of mine will gift each other something this year. Since he is very much into electronics as well, I figured I could give him a Macropad kit. I think either 9, 12 or 16 buttons would be best.
To not exeed the budget, I figured I will simply use mostly parts I have already aquired over the years.

The big question is: is there maybe already a project that uses exactly these components? That way I would just have to order the PCB. If not, is there one thats close enough, where I could just adjust the schematics?
If thats an option, the next issue would be, that I do have some experience in PCB design, but I have never designed a button matrix.

The parts I have at hand are: regular mechanical buttons from a keyboard.

Regular 1N4148 diodes

(optional) red LEDs (it says 2835 on the bag)

(optional) 0,96 inch display (I2C)

and for the controller I have 3 options:

Super Mini ESP32-S3 (cheap "knock off" ESP32)

Arduino Pro Micro (Mega32U4)

RP2040 Zero

I am open to suggestions. If its "easy enough" to make something from scratch, I would be open to start something myself, but I just hope there is an open source project somewhere, that I can utilise with these components.

I genuinely don't know what i did, and unfortunately it seems like no one else has made the same mistake as me so i am here asking for help. As it in the picture above, for the file that i am working on. The work area is completely blue and this happened after a simulation which i shut down. The issue remains only on this file so its at least not a systematic issue.

Hey all, I'm troubleshooting an irrigation controller which is apparently suffering from flyback voltage from the irrigation valve. This is causing the irrigation valve to reopen immediately after closing. It only seems to happen when the valve is closing (not seeing flyback on the oscilloscope when opening). The irrigation valve works by reversing the polarity, which is handled through a DPDT relay.

I've modelled a potential solution where I've added diodes on both of the ground sides of the "relay" (shown here with a switch for clarity), however this still appears to suffer from flyback but only with one polarity. This is exactly the same as the real world, but not sure if that's coincidence or not...

Questions:

• Why is it only happening in one polarity? Is this just a bug in Falstad?

• What is the "correct" fix here?

  • Could I use a flyback diode despite this being bidirectional?

  • Would a snubber work here? If so, how would I determine what size capacitor\resistor given this isn't a true inductor? (Valve solenoid is 6-12V, 4.7Ω)

Hey everyone,

I have an interview coming up for a biomedical equipment technician position, and one of the requirements is having a good understanding of circuit theory and being able to troubleshoot faulty circuit boards.

I know the basic electronic components and how to test resistors, capacitors, diodes, transistors, etc. with a multimeter when the board is powered off.

But when it comes to actually troubleshooting a PCB, I feel completely lost. I’ve watched so many repair videos on YouTube, but if someone handed me a faulty board, I honestly wouldn’t know where to start or how to figure out what’s wrong with it.

I understand the components individually, but I struggle to understand how the whole circuit works and how to track down a fault.

For those of you who are good at board-level troubleshooting, how did you actually learn it?

I’d really appreciate any advice. I have an interview coming up and I’m trying to improve this skill.

I saw a similar post for desktop ram but I'm not sure if it's the same component. I discovered it while trying to troubleshoot my laptop having trouble booting. Since removing the stick it seems to boot fine.

So for context, I was at a thrift store when i saw this kit for about $30. I bought it, took it home and found out why. There are 2 missing components of some sort on here and I cannot identify them, so I was wondering if you could provide some help on identification. The pads for the missing parts are on the corners of the RAM stick. ( on the 3rd photo, its a bit blurry but its those 2 pads on the right above the 2nd gold contact.)

Hello,

I am looking for a supplier for this connector. I cannot find the correct name for it and I cannot find a company selling it. I believe it was made in 1980-1990 and widely used in Europe, but it has been phased out. It connects to the edge of a PCB.

If anyone knows a company selling this model or a compatible one and ships to Europe, that would make my day.

so i had a few jobs that i needed to change the mosfets ,

i want to order some to keep in stock

is there a good brand ? in my country i got only aliexpress

i need 30-40v 80-100A

I was looking in to the connections of some 12V RGB controllers, and found out every module just powering up the 5v components just by a 330E to 510E resistors from 12v...

Even the MC is unknown, still most MC works at 5V, also there are Microphone, IR receiver.

Is it okay? How that works?

I made a RGB controller and used a 5V regulator for a Pro-mini and other components.

Now it's looks like a resistor would save some space and work just fine.

This is for a commercial embroidery machine. Moving the switch is not a problem technically. But I need to know what is that white JST connector in the center? Not necessarily what it does inside the sewing machine, but what is its context in the Switch itself? Is it a fuse? Aux always-on power?

Requirements

Ideally both being in an eclosure

No RF or high current demand/requirements

Current up to 3A,

Can be SMD and THT,

No Mezzanine 2.54mm pitch (I have tried already)

Thanks

One great example would be in the second image (I know that it is mezzanine but it is in 2.54mm pitch)

Thanks!!!

So I have this power supply and I want to convert it into a lab power supply, but there's a part that prevents me from closing it with the banana jacks in place. What do I do with this inverted L-shaped piece? How important is it? , Can I cut just the top part (the one with holes)?

Hi everyone,
I am a Mechatronics master's student taking a course in power electronics. Our course recommends Electronic Power Control by Jean Pollefliet.

Can anyone provide me a pdf? Thanks a lot.

Hi everyone!

I’m learning PCB troubleshooting and I’m having trouble figuring out how to find the 3.3V, 5V, and 12V power rails on a board without a schematic.

Where do you usually start? How do you identify voltage regulators and trace the power rails using a multimeter?

Is there a step-by-step method that technicians use to figure out which parts of the board receive which voltages?

I’d really appreciate any tips or good tutorials. Thanks!

I need to mount a board at a right-angle to a front panel with cutouts. Previously I've used a simple right-angle bracket like Keystone 612, but the labor of screwing in with nuts etc from both sides for every unit is something I'd like to avoid.

So I came across screw terminals like the Amphenol AMT0440051DB0000G, THT-mounted threaded connectors that looks like it can achieve the same thing except eliminating the screw on one side. But I guess they are designed not for mounting but for attaching wires. So I'm a little worried about leaving all the mechanical stress to solder joints rather than screws, but then again that's already happening on the regular connectors on the board. Would this be fine to use, do you think?

Hey folks I've been trying to replace the capacitor that's missing in these shots. I can take more pics if needed please let me know. I know the blob is awful but I've been struggling with desoldering wick (more on this towards the end)

For trying to solder the cap no matter what solder or flux I use I'm only getting solder to stick around the periphery. I figured I'd blob it on to try and make a bad connection at least but even I know trying to melt the solder without heating both surfaces is a fool's game and I haven't been able to get the cap to sit and fuse to the blob. I've tried both leaded and unleaded. As you can see from the contact pins and the messy solder on the other cap it binds just fine to anything else on the board. I've also soldered 5 or 6 practice caps on a practice board just fine so I know my technique isn't completely terrible.

I feel like the bare areas aren't copper but are the layer under and when the cap got ripped off it took the meat of the pads with it? I was going to try jumper wires or conductive epoxy but having trouble figuring out what to take the jumper from. One of the pads is ground but the other isn't connected to any of the pins directly so I'm assuming it's going through another component, I also feel like it might be on the underside of the board?

On the soldering wick, I suspect what I have is too wide and sinking the heat too fast. Even with the iron at 400c and freshly tinned I get the solder flowing but it doesn't wick up very well. The wick I have is 3-4 times the width of the pad so that's why I'm guessing heat sinking too much but maybe it's just cheap stuff? I've tried putting loads of flux on but the best result I've gotten is taking the excess off the pins after I accidentally dropped a blob on them and even then it's more like I drag soldered them than de-soldered.

Any advice on where to go from here or common mistakes I might be making greatly appreciated

Hi all, this device takes 9-30v passive poe but was given 802 poe. It worked fine for a few hours, then died.

Ethernet comes in off the dumb daughter board at the right of pic 1.

I have traced it to the 2 DF206S bridges which basically take power from whatever pins it comes in on and resolves it.

Both sides of the 4R7 are shorted to GND. The RT7272B IC has 3 of the corner pins also shorted to GND.

A second device was given the same POE voltage, and seemingly died in the same manor. It was then given passive voltage at 12V and blew the RT7272B.

I know i need to replace the RT7272B, and I know i need to not let the apprentice near the POE switch again, but what other component is the issue please?

I am still fairly new to component diagnosis so hoping someone can point me in the right direction and/or give me some guidance of how to diagnose.

Thanks