This TTL circuit has a well-known configuration, having been found in a Radio Electronics magazine from December 1980. The power supply must be 5 V.
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...