This circuit detects when an audio signal exceeds a certain level or even occurs due to an object falling, a door slamming or other. The circuit is from a Radio Electronics from January 1980.
This circuit is from 1990 documentation. It can be implemented with BC548 transistors instead of...
When you speak into the microphone of this circuit, the sound produced in the speaker resembles a robot...
This circuit uses an operational amplifier that is no longer on the market but can be implemented with a...