This very complex circuit in terms of the number of transistors was found in Radio Electronics from March 1966. The circuit is for low impedance headphones. The transistors are from the time.
This circuit for incandescent lamps was found in a 70s documentation. The circuit uses an SCR...
This circuit is from an Elementary Electronics from 1977. It can be assembled with relative ease...
This circuit detects the presence of strong signals from spy transmitters, enabling their...