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.
We found this circuit on the internet. The components are current, and the time depends on C1...
This circuit was found in an English publication of 1982. The operational can be replaced by an...
With this luminous remote control, which we found in a 1990 publication, using a flashlight you...