This is one of the channels of an amplifier suggested by Westinghouse in 1970s documentation. The circuit uses components from the era and no information about the transformer is given.
This circuit, from the 90's, is intended for operation with vinyl record players of the time, as...
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
Found in American documentation from the 1980s, this circuit prolongs the ringing of a doorbell or chime...