Found on a 1964 CQ this circuit is intended for tone frequency change modulation (FSK) telegraphic transmissions. It operates with signals of 2.975 and 2.125 Hz.
This old circuit from a documentation from the 70s disconnects a TV from a signal obtained on the...
This traditional complementary symmetry circuit provides 20 W of rms power at a load of 8 ohms...
Using a CA3130 and a power transistor, this circuit can deliver a current of up to 500 mA with the...