This high sensitivity circuit was found in the July 1992 Radio Electronics magazine. The circuit drives a buzzer, but a relay can be used to activate an external load.
Originally designed for use in an FM receiver, this 1990 circuit can be adapted for other types of...
This 3-transistor timer was found in the January 1994 issue of Electronics Now magazine. The...
This circuit was found in a 1974 publication. It consists of a voltmeter for high voltages, up to...