Hello, I build and light many different SciFi theme models. For my own entertainment and in the last couple years, others too. What I’d like to have is a circuit that would randomly light 8 to 12 LEDs as an effect for the representation of an old style computer. Sort of a representation of the computer thinking or calculating you might have seen similar in an old TV show. I’d rather not deal with programming an Arduino or microcontroller. I’m thinking this could be designed with just digital... Random LED panel ..read more

I have a fairly simple 555 timer circuit. I am using either one Li-ion coil cell at 3V, two of them in series for 6V, or even 3 for 9V to power the design. The output is an LED meant to flash at the right timing. My output voltage is acting a bit odd. Regardless of if I use 3V, 6V, or 9V, my output voltage from pin 3 to ground is 1.8-2V. I am using the NE555 timer from TI. I thought the voltage drop would be less than 1V. Any ideas on why the output voltage is the same regardless of the... 555 Timer voltage drop issue ..read more

Hi, I'm working on a setup with a filter and some electronics to get an analog signal ready for a ST microcontroller (STM32H723VG). I want to simulate everything, even the part inside the microcontroller that handles the signal. But the problem is, I can't find the info I need in the microcontroller's manual. The manual does have a table that shows how long it takes to sample different signals, depending on how much resistance the source has. But I'm not sure how to use this info to figure... STM32H7 ADC characteristics ..read more

Hello folks im new here, I have a problem with a part a can't find out what it's called to be able to order one it has no names on it just some numbers. Maybe someone can identify the thing for me would appreciate it ..read more

Hi, I was wondering if in the following schematic DP83825EVM ,from texas Instrument, there is a mistake on how is the transformer HX1198FNLT is connected to the PHY IC and the RJ45. It seems like the Common mode choke is on the PHY side instead of the connector side. if it is correct, why would it be useful for? Thanks ..read more

Hi everyone and thank you for your time, I am having a problem where on my car my position lights work only during night time if left on automatic and in my country by law you need to have at least position on in daytime so I wanted to make them work when the engine is running during the day but still leave them work with automatic lights as intended... The way I plan on doing this is by adding another positive wire that will connect directly to the led but I need a circuit or a component... Need help finding the adequate component ..read more

Can someone explain to me how this works? I'm trying to bench test the DC motor that operates this valve and I'm struggling how a DC 12v system would generate a negative PWM signal for (EXM-). I put a scope on the controller of the motor, but didn't see any frequency. Looking at the below, I inferred that the motor received a PWM frequency to open and close and a source voltage to an angular sensor to determine being open or closed, but apparently that's incorrect, so if someone could... Need help with how a circuit functions ..read more

Hey everyone, I'm really excited to be part of this community! I've recently started using EDA software with EasyEDA, and I'm currently designing some PCBs for my home assistant project. For now, I'll be using a breadboard for the computing side of things since my skills aren't quite there yet. If I happen to damage an ESP32, I can easily replace it. I'm planning to integrate an LED strip into my home assistant setup using ESP-Home. I'll be using 12V LEDs, not exceeding 3A. That's why I... esp-32 LED driver ESPhome ..read more

Hi everyone. I am building a Theremin circuit. It is working with hand gestures. One of it is oscilloscope and other is amplifier circuit. It takes data with camera. Then DAC turn the signals to analog signals. Left hand will control amplifier circuit and I have problem about it. I will control volume with amplifier circuit. I am not sure how should i design Amplifier circuit? I mean does digital pot works and cut off frequency for oscillation circuit is important for the amplifier circuit too ..read more

Hello , i have designed a basiclow pass filter circuit using next i want to match it to the input and output Z=sqrt(L/C) =0.707ohm so i put 0.707Ohm on the output to match it. so there are no ringing overshoot but i get a -6dB value at the output. In filter design i need to have 0dB output. Is there a way to get 0dB responce? Thanks ..read more