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.
The purpose of this circuit found in a 1967 GE SCR manual is to control a heating element. The SCR...
We found this circuit in an old documentation. The operational amplifier of the time can be...
This power control from a 1968 Motorola manual shows how to use a contemporary diac as a...