This circuit is from an old documentation from the 80's. The circuit provides an output signal for a warning or alarm system that indicates when a fuse or circuit breaker opens.
We found this circuit in a 1985 technical publication. The circuit uses PUTs to drive lamps....
This high-powered megaphone circuit is from a Radio Electronics from December 1964. Note the use...
This amplifier with differential input uses two old op amps but can be implemented with modern op amps....