Hello, I have seen a circuit including the two chips above that acts like a "visual effect" associated with a science fiction "universal translator". I have a functioning board that my friend bought and only see a few resistors, caps, and the two ic components. I thought it would be fun to try and breadboard a similar circuit.
When you speak the microphone (little condensor mic I believe) picks up your voice and you see the leds light up (there are 6 Leds.) With softer sounds, only one led lights up, as the volume increases--you see more and more leds light until they are all lit when you speak with a loud voice.
I have tried to hook up a basic 20 gain and 50 gain and 200 gain 386 amp and send the signal into pin 5 of the lm3914 but have had no luck at all.
I tried to make a simple amplifier with the 386, with a speaker attached with the above gains and I get a tremendous squealing from the speaker when I test it. I understand that this is unwanted oscillation and can be caused from a variety of things. I read that a cap across the battery terminals can solve some of this but bottom line I would like to know can you just simply output the 386 into the 3914.
any ideas? suggestions would be greatly appreciated.
thanks,
Daniel