This circuit with TTL compatible output was found in a 1968 US documentation. The circuit is powered by 5 V and the frequency can be changed by changing the crystal.
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...