This circuit supplies a voltage of 42 V, plus a symmetrical voltage of 12 V with 1 A. The voltage regulators must be mounted on heat sinks. The transformer is 35 + 35 V with 3 A.
This circuit generates sinusoidal signals between 300 and 3000 Hz. We find a 303 Circuits from the 90's....
This amplifier for audio transmission lines was found in a 1961 American publication. The critical...
Old phones with dials can be used in a simple home intercom system, as this circuit from Popular...