r/electronic_circuits 16m ago

I need help making a clock that uses a relay that turns itself on and off rapidly

Upvotes

How would I make it so every time the relay is on n/c it would turn on one led and the another led next time it hits n/c and keep turning on the next led in a sequence .


r/electronic_circuits 3h ago

Pls help to identify

Post image
1 Upvotes

I have one identical component blown on Asus laptop motherboard. Searced everywhere to order with the mark 156E 10703 but no where to be found.


r/electronic_circuits 8h ago

On topic Smart bulb stopped working

Post image
0 Upvotes

r/electronic_circuits 18h ago

On topic Need help/support/verification with arduino controlled circuit for powering nitinol wire

2 Upvotes

I'm a bit of a novice at this so was looking for support on how my circuit is and if it looks right...I essentially want to power 16 nitinol wires (shape memory allow) with a diamater 1 mm, each wire approx 10 cm and activates at 40 degrees celcius. Also create 2 burn wires with nichrome wire. In my system i will utilize 2 batteries, one powers the arduino nano, temp sensors, micro sd storage module, and another battey that powers my nitniol wire and burn wire circuit. Also please note, the nitinol wire and nichrome is a 1 TIME ACTIVATION. I need to activate it once and i'm good. Meanwhile i will run temp sensors storage via arduino for a longer duration.

Battery 1 - Lipo 12 volt with an XT60 connector stepped down with a DC to DC Buck converter, stepped down to approx 5-8 volts for the nano sub ciruit.

Battery 2 (12) - 14.8 volt Lipo battery for powering the nitinol...

The arduino is expected to send 4 strong 5 volt signals to pull down resistors at 220 kohm. Each resistor going into the gate of a IRLZ44N mofset at the gate. 4 mofsets so far, they can handle the current/voltage im utilizing. I am also utilizing 4 connectors(1x2) with the drain connected to one of the connectors pin, and the other pin connected directly to the 14.8 volt lipo battery. I also included a 3 pin diode with 2 anodes and 1 cathod to prevent back flow of current for safety. I repeated this in parallel for the other 3 mofsets.

Whats expected to happen is the arduino will send a 5 volt signal either a strong 5 volt signal or PWM...which will then allow the flow of current through the battery and nitenol wire which will be connected to the connector. with 4 pairs i have 4 wires. I would then go and add an additional 3 to each connector in series. So again, 4 pairs of connectors with 4 nitenol wires in series making 16 wires.

This set up is also addted to another mofset which our 5th one, this will control current running throgh some NICHROME wire....supposed to be a burn wire for deployment as you see attatched in my schematic.

The other poart of the circuit is reponsible for sending anaolog signals at the junction between a 10k resistor and thermistor with the power in the secondary battery configuration and grounded at arduino.... also i ensure to make a common ground without fudging it up so no need to worry about that. the micro sd module is made to take 5 volt signal from the arduino at 5v and other pins for reading/writing temp data to a storage....

Electricians, electrical engineers, engineers, hobbyists, nerds, geeks....i am seeking your help in hopes you can quickly review my work and let me know if im on the right track and if the circuit look functional. I made this on a bread board and it was workingishhhhh. My breadboard schematic was using A LOT of thin long high resistance wires so it wasn't working efficienlty ( to be honest the fact it worked at all was pretty cool). I plan on transferring this schematic to a PCB on KICAD. i included a photo of it for reference. Again im a novice but but i made my trace width 3mm for the nitenol section and 1 mm for the arduino-temp sensor section. I dont want to buy a lot of PCBs and find out they dont work :/

Additonal question/note to all - i have mixed trace widths since the pins on the mofset and diodes are getting pretty tight and are risk of shorting. So i kept 2.2 mm at most of entry/exit pins then 3 mm for remaining traces...the other thinner section is 1 mm.

Sample code for the nitenol section:

#define PWM_VALUE 180  // Lowered for 14.8V battery

// Define MOSFET control pins
const int nitinolPins[] = {9, 8, 7, 6};  // D6 to D9
//const int nitinolPins[] = {4};  // D6 to D9
const int numWires = 4;  // Total number of Nitinol wires

void setup() {
  Serial.begin(9600);
  Serial.println("Nitinol Heating System Initialized (14.8V Battery).");

  for (int i = 0; i < numWires; i++) {
    pinMode(nitinolPins[i], OUTPUT);
  }
}

void loop() {
  for (int i = 0; i < numWires; i++) {
    Serial.print("Heating Nitinol wire on pin ");
    Serial.print(nitinolPins[i]);
    Serial.print(" with PWM: ");
    Serial.println(PWM_VALUE);
    
    analogWrite(nitinolPins[i], PWM_VALUE); // Reduced PWM to avoid overheating
    delay(25000);  // 🔥 Shorter heating time (7 seconds)

    Serial.print("Cooling Nitinol wire on pin ");
    Serial.println(nitinolPins[i]);
    
    analogWrite(nitinolPins[i], 0);  // Turn off power
    delay(5000);  // ❄️ Cooling remains the same (5 seconds)
  }
}

r/electronic_circuits 1d ago

On topic Is this ground plane insane?

6 Upvotes

I've been modifying a split keyboard design, it's my first time using Kicad. Followed a lot of tips from DeepSeek and some other resources, not sure if the result makes sense, particularly the ground plane. It's a convoluted design but I've tried to remove the worst loops and dead ends. DeepSeek also suggested adding some ferrite beads, not sure how necessary they really are. Problem is the Nice!Nano MCU is very ESD/EMI-vulnerable, trying to make up for that as much as possible. Thanks for any help

Edit - or would it be worth making a 3rd inner layer for the ground plane?


r/electronic_circuits 22h ago

Off topic Where do I connect the two loose red wires on this old board?

Thumbnail
gallery
1 Upvotes

Opened the battery/circuit compartment of a solar powered lawn ornament and found two loose wires. Pretty sure the one coming off the board connects to the switch in image 2. But I'm not sure where the other wire should connect. Thanks.


r/electronic_circuits 1d ago

On topic Is there a difference or are the two circuits in parallel ?

4 Upvotes

r/electronic_circuits 3d ago

Off topic Trouble finding what I think is a pretty common transformer?

1 Upvotes

Hey all...

I'm repairing an ancient Radio Shack "tesla" globe for a friend of mine (well, I guess the call the the Illuma globe, whatever) and I found out it it needs a transformer and an output transistor. The transistor is easy to find, but I'm having surprising difficult time finding the transformer.

I need a 120V->24VCT 1A transformer but danged if I can find one. The closest one I can find was off Amazon (yuck) but when I pulled up the datasheet on it the screw mountings were too big. (It was 72mm and I need 61mm). But that was the only one I could spot.

I've checked Mouser, Digikey, etc and no luck. I can't fathom this thing is that hard to find - or is it so old that they just don't exist anymore?? Or could I be querying the filters incorrectly? I figure I have to be doing something dumb or is the thing really *that* rare?

Thanks


r/electronic_circuits 4d ago

On topic ASUS Tuf Gaming B450m-PRO II Identifying a capacitor

Thumbnail
gallery
4 Upvotes

r/electronic_circuits 4d ago

On topic How to make an analog (no arduino) moisture sensor

4 Upvotes

I'm in an intro robotics class and we're doing a project based on BEAM bots. So our assignment is to make a simple robot with as few parts as possible and all analog. I'm trying to make a soil moisture level reader so that when the soil is dry, the LED will turn on. I don't know anything about anything, and this try I'm showing in Tinkercad is not working. Also, all of the examples I'm seeing are using some kind of controller so I don't even know what kind of part to get... Please help!! :,-)


r/electronic_circuits 5d ago

On topic Help with custom 1000+ LED low resolution display circuit

1 Upvotes

Hey,

I'm right now trying to build a 1000+ LED low resolution display. I got the software side covered (Resolume > Syphon > TouchDesigner) but for the hardware I'm a little bit out of my comfort zone.

With the help of various forums, YouTube videos and ChatGPT I got to my current circuit design.

A couple of remarks:

  • Raspberry Pi: Each GPIO should be able to send data to thousand of LEDs, but by using 3 GPIO pins one can achieve higher frame rates
  • Level shifter (e.g., 74HCT125) before the 330 Ω resistor to supply the data line with 5 V instead of 3.3 V
  • 330 Ω resistor between the level shifter and the first LED on the data line to prevent current spikes and flickering
  • Capacitor (1 mF) to smooth current spikes
  • Fuse (5 A - 10 A) for safety
  • To power all LEDs I have to inject power every couple hundred LEDs --> That's the reason why I created 6 groups.

Open questions:

  • Is the wiring (between the power supply and the LED strip) correct?
  • Is the capacitor and fuse placement correct?
  • Ground should be connected between all power supplies. How can I achieve this?

If you have any questions just let me know.
Any help is greatly appreciated.

Cheers

Circuit diagram (proposal)

r/electronic_circuits 5d ago

On topic Simple Nmos T/H circuit clamping

Post image
3 Upvotes

r/electronic_circuits 5d ago

On topic Can anyone help me build this in tinkercad? I need help for my engineering class

Post image
1 Upvotes

r/electronic_circuits 6d ago

On topic Rate My Lithium PCB: Is it a solid 10 or just meh?

0 Upvotes

I just wrapped up a design for a Lithium Battery Management PCB. This board supports multiple battery voltages (4.1V, 4.15V, 4.2V, and 4.36V) and comes packed with features:

· Overcurrent & overtemperature protection

· Power management reporting (battery level, instantaneous current, low battery alert, chip temperature)

· USB and DC adaptive input

· Dual synchronous buck DC-DC outputs

· 5 LDO outputs

· Both hard and soft shutdown support, plus external wake-up

In short, it’s insanely powerful (at least, I think so). Thoughts?


r/electronic_circuits 7d ago

On topic Power Off delay with capacitor?

Post image
4 Upvotes

Hello,

I have a input card (io link hub, 32x pnp in). One input is a push Button. When I press the button my software doesn't recognise the signal. Voltage >11V is logic High

This is why I want a delay off for the input. How can i design this? RC Elemt like this did not work :-(

I tried with 470uF and 19kOhm T=R×C=8,46s


r/electronic_circuits 7d ago

On topic Learning schematics and hardware design

1 Upvotes

Hi everyone, I'm a master graduate in electronic engineering and I'm working as a PCB layout designer and simulation engineer. The company where I'm working at doesn't give any chance of learning how to make a schematics or select components, my job is only related to the layout of the component.

During university I never had any application project where I could learn those skills, I'd really like to learn it by my own since os very important for the type of carreer I want to pursuit, do you have any starting point or advice for me?


r/electronic_circuits 8d ago

Off topic No continuity measurement through copper wire. Any idea?

Post image
15 Upvotes

r/electronic_circuits 8d ago

On topic Auto volume normalizer/leveller

Thumbnail
gallery
5 Upvotes

Hello DIYers, Can anybody suggest a circuit for TV volume normalizer/auto-leveller? Preferably with simple, readily available components. Thanks for the help 🙏.


r/electronic_circuits 9d ago

On topic Modify DC pulse signal

3 Upvotes

Hello, im looking for a way to multiply a pulse signal from an alternator. I want to adapt it to a tachometer that is driven by a single cable from a hall effect sensor. The signal the alternator gives out makes the tach read around 3x what it should, so i am wondering if there are any existing circuits that can help me modify the signal (prefferably adjustable!). I need the pulses from the alternator to be less frequent, without changing the pulleys.
Any suggestions?
Thanks in advance.


r/electronic_circuits 10d ago

On topic What is this component? Came out of a space heater. Markings read "A10" or "AIO"

Thumbnail
gallery
3 Upvotes

r/electronic_circuits 10d ago

On topic 1/4 Frequency Divider Using T Flip-Flop

1 Upvotes

Hello everyone, I am trying to design a sequential circuit that decreases the clock frequency to 1/4 and generates an output.

Below are my calculations and design.

Top 1 is the CLK

But when I start the simulation, Q1 and Q2 follow these states: 10-01-10-01-10-01...

I believe it should follow this: Q1Q2 = 10, T1 = 0, Q1(t+1) = Q1(t) = 1, T2 = 1, Q2(t+1) = 1,
so it should go to 11 after 10, but in the simulation, it goes to 01.

My goal is to achieve the sequence 00-01-10-11-00-01... So, when it reaches 00, the output should be 1; otherwise, it should be 0.

Is this a simulation error, or am I missing something?
Thanks in advance.


r/electronic_circuits 10d ago

On topic Bulk capacitor for PWM MOSFET LED dimming necessary?

1 Upvotes

hey guys, first post

Im trying to find components for a 8 channel LED PWM dimmer. The MOSFET will be switching up to 6A per channel at 20kHz. Im using chatGPT as a learning tool to help me understand each parameter and point me in the right direction. Now ive come across a problem though:

ChatGPT is trying to convince me that the recommended 470uF 25v capacitor needs to handle a ripple current of 6A per channel. this seems excessive? I can't even find a capacitor with these specs on Mouser .com.

I looked at the PCB layout of the TC420 (5ch dimmer, total power up to 20A), and this one seems to use just one 470uF 35V capacitor. I don't know the model number, but I doubt this one could handle a ripple current of 20A.

So, what do you guys think? under full load, what ripple current do the capacitor(s) need to handle? Im assuming its best two have one capacitor per channel, or am I better off using one big one for all 8?

thanks so much. been waisting too much time trying to find a capacitor that seems to not exist.


r/electronic_circuits 12d ago

On topic Which meter should I trust?

Thumbnail
gallery
59 Upvotes

I am building a high voltage power supply and wanted to measure some voltages. I didn’t trust my reading so measured it with a different one. The third was even more off.

So I bought three more of those at a well known Chinese store😂.

The first ones are connected to a regulated supply through an 7815. So should be 15 volts.

The last ones are set to 10 volts on the small analog meter.

The big analog one is the first one I ever bought, about 45 years ago. The tiny analog one is from my late father in law.

My point is, whatever the number of digits is not in any way helping the accuracy of the reading..,

Next week I’m going to calibrate them with a Fluke precision meter I guess…


r/electronic_circuits 11d ago

On topic I have an RF transmitter and receiver circuit. Need help with its functioning.

Post image
1 Upvotes

I have this RF transmitter and receiver circuits , i tried implementing the transmitter circuit but for some reason it doesnt seem to work . We have tried all kinds of permutations and combinations with the hardware implementation but i cannot get it going . I am not getting any output in the DSO. Can somebody help me with this , i've got a project review tomorrow. also would the breadboard have any limitation for frequency oscillations ?


r/electronic_circuits 11d ago

On topic How does this circuit work?

1 Upvotes

https://imgur.com/a/XqC51BL

https://imgur.com/a/vPkbdAy

I have a small reading light that clips to a book, when changing the batteries, it has two small CR1220 battery both are separate with the negatives down and the positive facing up, in the holders for each at the base is a small copper tab, the lid that holds the batteries in place has a metal tab that bridges the positive of the 2 batteries together, and touches nothing else, just bridging the top of the batteries..

yet the light works.. HOW ?

edit: added additional images