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.
Found in Popular Electronics from 1969, this circuit uses a neon lamp from the time that had...
This receiver was found in the Radio Electronics magazine of March 1953. It tunes to the medium wave...
The figure shows how to use the XR2206 to generate sinusoidal signals in a different way. The...