Found in a 1967 Electronics World, this preamplifier uses an integrated circuit from that time, difficult to obtain today. The maximum frequency is 15 kHz.
This circuit, found in 2002 documentation, triggers LEDs when a phone call is received. The LEDs...
This simple version of a function generator with the XR2206 was found in the May 1977 issue of...
A pulse triggers this 800 Hz horn for a time determined by capacitor C1. Powered by 5 V the...