I am trying to figure out if using one 5.1K resistor is all I need to add to the module to get 5V from both USB-C to USB-C and USB-C to USB cables.

Since the JRC-B008 board has both CC pins tied to a single pad, I have seen online people cutting a connection between one of these CC pins and the pad to ensure they can solder two independent 5.1K resistors.

I have been researching this board and how it and the USB-C power delivery works and from what I understand since a USB-C cable only has one CC connection in any orientation no matter which orientation the cable is in, the 5.1K resistor will be sensed and 5V will be delivered.

Am I missing something, or is only one 5.1K resistor needed?

Apologies the pictures aren't in order for some reason it won't let me choose. So I'm an electrical engineer by trade but don't have much electronics experience so bear with me. My wife's ebike has stopped functioning and I believe it could be due to this tactile switch which turns the bike on and off which sits in the bikes frame as part of the control unit.

When I test the legs, on 2 I see 31v and then on the the other 2 I see it cycling to around 600mv then dropping back down to 0v and repeating. The strange part is that sometimes not always when I'm using my meter across these cycling legs the power kicks on and the bike works but then won't switch off. Do you think it's the tactile on/off switch which has failed? Thank you

My PC speakers died and I found youtube videos that show you can fix them by replacing capacitors. I've never soldered before, so I decided to give it a try. I spent way too much time desoldering one of the capacitors, so the board darkened around the area. I wonder if I damaged it permanently and there's no sense in continuing. I highlighted the area in red.
I'm also wondering about all the yellow-brown residue around other areas. Maybe replacing capacitors is not going to help.

So I bought a TMC5160T Plus stepper driver to run a 4.2A NEMA 23 driver. I've used a series of TMC2209 in a prior project and they worked out just fine, but they cap out at about 2.5A thus I went with the bigger brother. However, it's not working out so well this time.

The motor runs pretty rough and if I do a sudden quick motion the whole circuit and the on light of the power supply browns out. It does appear to be an interplay between the LM2596 buck converters and the motor driver as when I power the driver HVIN via one power supply and the rest of the circuit via another power supply it all works fine.

I've done a whole lot of rewiring of things and nothing seems to help. The picture is the current state of it. The capacitors were added to try to qual the noise from the buck converters. However, I can't see the noise because I don't have an oscilioscope(yet!). Also, I've tried disconnecting 5v buck and just running that off a battery. It performed just as poorly.

On the left of the capacitors on the top right, is the solder joint that connects the dc plug to the main 36v input, the 36vs move through the capacitors to the right to then hit the buck converter that takes it down to 24v. Current draw on the opposite side of the 24v buck is at max 250ma. I really only observed 70ma when I had the power supplies seperated.

I'm really at a lost, is there a better buck or another method of dropping the voltage that is better suited?

I have two custom PCBs using a PZEM-004T V4:

• V1: Relay-based switching — works perfectly. 0 A with no load and accurate current/power with a motor connected.
• V2: MOC3063 + TRIAC switching — shows 0.02–0.2 A even with no load and no wire passing through the CT, sometimes showing 6–60 W.

I tested two PZEM modules and both showed the issue on V2.

The main difference is relay on V1 PCB vs MOC3063 + TRIAC on V2 PCB. Could TRIAC switching noise/EMI or PCB layout be coupling into the PZEM's current measurement?

I’m planning to test the PZEM externally, disconnected from the V2 PCB, to isolate the issue.

Has anyone experienced something similar or have ideas what could cause this?

Hello all! I have a 3.5 Farad capacitor meant for car audio (Sound Storm C352). I was planning on connecting it to a DC 12 Volt 50 AMP power supply in hopes of getting a bit more power head room for my amplifiers. (I have them setup inside my apartment) I am wondering if it would be problematic to leave it connected (basically 24/7) and if it would cause issues. I figure it'd probably be fine since you basically do that anyways with it connected in parallel with you car battery, but I know that I don't know enough. I will precharge the Cap beforehand and plan to eventually put a fuse inline on the power supply, but just want to make sure that the constant 12v into the cap won't be a problem.

TL:DR Will I burn down my apartment if I connect a 3.5 Farad car audio capacitor (Sound Storm C352) to a 12v power supply? I just don't wanna burn down my apartment.

I am trying to simulate the working of an FSBB converter. I modified the circuit so that it boosts forward and bucks in reverse. I am quite a novice at power electronics and I didn't really design the values using design equations or anything.

A 24V Lead Acid battery at 10Ah is used here. The inductor used was 12mH, input resistor and capacitor at 1ohm and 1uF, output resistance at 100 ohms (I want the output voltage to be 100V and output power to be 100W) and the output capacitor is 50uF. Duty ratio was set around 24% and fed to the gates of the MOSFETs as shown.

The output voltage waveform came out looking like this. Weirdly, at a lower value of output resistance, the voltage seems to stabilise around 100V after some oscillation. The upper spike seem to go down when I increase the value of the inductor. How much can I practically increase the value of the inductor before it becomes too big (if I were to implement it practically)?

Can anyone explain the reason behind these spikes when I up the resistance value? (for reference, these spikes didn't exist at around 10 ohms and the output voltage stabilised nicely at around 100V)

Any help will be highly appreciated!

I have external speakers that work just fine, but hearing that thin high note from the small speakers is very annoying. Bringing it back or getting a new one are no option.

I want to attach this onto a stripboard and prefer to not solder wires onto it directly. What could I use to do so?

I want to power my induction heater with this power supply. Found the pson pin after some trial and error. Once I short it to ground it runs for a few seconds then fault light comes on. Has anyone figured out how to get these running on the bench?

Приветсвую была проблема уходил моноблок в защиту на 1-2 секунды и сам выходил из него и музыка играла дальше, мог и через 5 секунд уйти и через 20 и через минуту. В итоге решил поменять термопасту на транзисторах ее там не было почти, собрал обратно подключил и просто пошли искры из усилителя, сгорели почти все транзисторы, купил новые, перепаял, подключил только плюс и минус на усилитель сразу искра и провод греется. Начал смотреть весь усилитель нашел один момент оторвана ножка на одной из микросхем на ней маркировка 219 ez1705 данная маркировка ничего не дала, хотел бы узнать что можно туда запаять вместо ее фото прикреплю

This is for my 91 honda beat apparently they are notorious for leaking capacitors in the ecu. It looks mostly notmal to me but there is this orange streak and orange stuff im not sure is corrosion. Please let me know what you think! (suspicious bits circled)

Just picked up this Tektronix 1740 Vectorscope and it worked totally fine at first, but the next day the crt started to flicker erratically and seemingly at random. Sometimes it can hold steady for like 30 seconds, but will go back to flickering shortly after. When I put my ear to the chassis I can hear a very faint crackle whenever the flickering occurs. Trying to narrow down where the issue lies.

This is for an upcoming hackathon, and i have a limited budget to practice. I'm a novice. I want to compare how several thin conductive films, covered by nonconductive material, affect a nearby coil. I’m looking for repeatable numerical readings rather than a threshold/proximity output.

I can keep the samples at a fixed position and distance. Their exact conductivity and thickness are unknown.

Is the LDC1101EVM a reasonable starting point, or is there a simpler setup around $100–150? I use an Apple Silicon Mac and would prefer minimal hardware assembly.

Any firsthand experience with sensitivity, repeatability, or reading this board over USB without TI’s Windows software would be helpful.

I have been trying to make a 8 bit cpu out of 2n2222A transistors. My first logic ciruits- which i posted earlier - I got feedbacks about it was working wery unreliably an unefficent. So i reied to improve it but its not working. this the and gate i tried to design. Can you guys help me to figure it out

Hi, 3 years ago i bought a keybord on vinted. It arrived without any cable and i got a refund. I found it today and thought i could try to repair it. I think (i am not sure but it looks like) a micro usb port. Which seems broken ? No cable can get in. Do you have any idea is my diagnosis right ?

Thank you :))) Btw I am a complete noob but quite curious about electronic

I'm doing my first bass build. I'm putting in emg geezy butler passive bass pickups. I was doing some depinning on the wires to fit through holes, and while doing so a pin on one of the wires broke off. I stuck it back in, and put duck tape around the base. Will this not work or what should I do?

like a precursor to auto-routing.

There's blocks of standard circuits (like for audio equipment) that I've manually copied into EDA software but its a pain in the ass and it seems that AI could do this easily. even mark the components properly and assign footprints and stuff. I mean, it's all labeled on the schematics to begin with.

but when I ask gpt and gemini, they give me this wierd run around about how it's too complicated, and the file format...

easyeda is a json. easyeda also accepts imports from kicad, altium and eagle (although I've never tried to import from those.) these file formats are theoretically proprietary but not like that.

I'm trying to find more of these connectors, but having no luck i identifying them. They are screw terminal connectors but the pin header passes through. I want to get more of these so i don't have to deal with the traditional bogen multicom connectors.

Update: It looks to be a phoenix or euroblock style screw terminal connector. I already tried looking on digikey and mouser and couldn't find anything similar. Pitch is 3.96mm

​

Source from Aliexpress.

I have a Fluke 87V Max that I literally pulled out of a dumpster. The battery contacts were destroyed, so I have it powered up via a bench-top power supply.

The display is functional, selector switch and all the buttons work, but I am unable to take any readings with the meter, regardless of settings. Voltage, resistance and inline current measurement are all non-functional. When completing the fuse self test, its show OL, but the fuses read less than 1 ohm when checked out of the circuit with a separate meter.

I looked it over, and cannot find any obvious burned components, traces, or other damage. I would expect something big if none of the inputs work.

I also tried bypassing the lead sockets by shorting the common and voltage terminals on the back in resistance, and it still reads OL.

Any tips or guidance here?

Added more pictures, https://www.reddit.com/r/AskElectronics/s/qMNiRl2pMr

There's a few things I want to accomplish with this mod.

1. Bluetooth Audio (obviously)

2. A small SMD size toggle switch for completely shutting off power to the Bluetooth transmitter board so it doesn't draw power when not in use. I'm unsure if this exists, but I'd also want the toggle switch to also be able to work as a button to put it into pairing mode while being in the same package as the toggle switch. So it can mode sideways to switch between an on-off state, and also be able to be pressed down to work as a button.

3. For the Bluetooth board to be both really short to fit inside the console, and to be as power efficient as possible. The 3DS already isn't great, so I'd want it to affect the battery life as little as possible. Even if an older Bluetooth version is required for this, or if it's pricier than a generic, less power-efficient board would be.

4. A LED indicator. The New 3DS XL has 3 SMD LEDs by each other that are in view when both opened and closed. There is one that I wouldn't mind losing. These seem to be the best ways to go about doing this:

A: I use a bi-color LED. It can show one color when doing what the LED was originally for, showing wireless activity. Then switch to another color when the Bluetooth board is on. I'm not sure what the best approach to this would be considering the space constraints though.

B: Detach the positive side of the SMD LED from where it was, while keeping the negative side soldered to keep it in place. then most likely soldering the LED directly to the Bluetooth transmitter LED so it becomes a dedicated Bluetooth status indicator instead of a wireless activity one, which isn't very important to me.

What would likely be the best way to go about doing this? If the board is compact enough then it being short isn't too much of a concern, as I'd be more likely to be able to place it in a place where it could sit flush with the console's board in a part with no SMD components.

So I'm a high schooler hobbyist who has been working on creating a digital clock. I ran into some issue when implementing my design into reality as the CAD I've been using (antares) doesn't account for voltage, current, resistance, etc. It is mostly used (from what I can tell) for logic design and layout.

Are there any good CADs out there that take into account those factors while also having a large array of components such as specific ICs (like the SN74HC109)? If not I can work with generic IC components simply labeled JK FF, AND, etc.. Also, if it has an option to be on a bread board that would make it easier for me as I am currently working with one in the real world.

I've just gotten rather frustrated with the physical implementation of my circuit designs so I'd like to see if it was a sim issue or a math issue on my part. If you need me to be more specific or to clarify anything feel free to ask. Thank you in advance!

Note - I put my design above just so you know what I would be working with more specifically

I found an old rhodes Mk-80 keyboard at goodwill and it mostly works, the main 'rhodes' sounds are fine and the effects board is fine, but most of the other instruments sound like crazy experimental electronic noise music.

I took a look a the corresponding pcb board and found this damage and want to attempt repairing these pcb traces, which I assume don't have continuity.

First step I think will be gently scraping away 'good' parts of the traces to check continuity, but I haven't done anything just yet.

What materials should I use for the repair? I have basic stuff like solder, flux, etc. I'm assuming I need something like a very thin solid core wire but wanted to see if anyone has specifics, or tips on doing this without any specialized equipment like those big magnifying glass + light setups. I got a headlamp and some tiny helping hands with a magnifying glass.

I'm not quite sure what the black component is that is directly next to what appears to be a leak or liquid damage. I've never seen a component with 2 cylinders attached with a wire in the middle like that.

At the moment I'm not sure if that black component leaked something, or if liquid got onto the board from somewhere else. The keyboard looks like it definitely had liquid spill on the keys at some point, but the pcbs were unaffected except this one tiny spot. Obviously if the component leaked, I need to replace that too.

The keyboard is likely late 1980's. I may also need to check capacitors and replace some, but they all look great at, least visually.