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 found in an Elektor from the 90s. The circuit is critical, requiring a very...
This circuit using an operational amplifier was found in old American documentation. It can be...
The relationship of values between R1 and R2 determines the reference voltage for this circuit that...