This circuit was found in a 1980s Intersil documentation. The integrated circuit used is not common today. The power supply must be symmetrical.
This commercial circuit is from a Japanese magazine from 1967. It uses germanium transistors, and...
This circuit can be used to drive relays, solenoids, motors and other loads according the...
This circuit is based on the small keychain that responded to the sound of a whistle and were...