This circuit was found in an 80's EDN. The circuit uses a current common CMOS, the 4093 powering an LED. Trigger adjustment is done in a trimpot.
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...