This circuit activates an old cassette recorder when the phone is being used, thus making it possible to record the conversation. The circuit is from a Hands On Electronics from the 90s.
This circuit allows 220 / 240V shavers to be used in the 110V network. The diodes can be general...
Found in July 1975, Radio Electronics magazine this circuit can use any operating circuit,...
Here we have in the figure the configuration of the circuit as a conventional Darlington. In this...