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 was obtained in the Linear Applications Handbook of the National Semiconductor of...
This circuit is indicated for audio tests, the tracks being selected by the capacitors. The...
This circuit can be implemented with more modern operational amplifiers like the 741 and its...