This circuit is from an American manual from 1975. The transistors are types of the time, but equivalents can be used, as well as the relay that can be according to the supply voltage.
This circuit is used to protect an amplifier from excessive power output that would cause problems for...
This circuit was found in a French magazine Toute LÉlectronique from 1978. Transistors are not...
This circuit was found in documentation from the 50's. The circuit uses transistors of the time...