We found this circuit in a 1968 Electronics World. The transistors are from the era and information about the transformer was included. Transistors support current equivalents.
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...