Found in the 1976 Siemens transistors manual, this circuit works with AM or FM IF signals. In the diagram information is given for the coils.
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...