This circuit for controlling high power LEDs (up to 2A) is from a General Electric documentation from 1970. The circuit serves to modulate a transmitter in PWM. The circuit serves as a shield.
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...