This test circuit for transformers connected to the power grid makes use of a variac. We found it in an old American documentation.
This interesting circuit for analog TV selects the first line of a frame. The circuit was found in a...
This circuit was found in a 1967 EEE. The components are from that time, but the circuit can be...
Found in a 1968 documentation, this circuit provides symmetrical voltages determined by component...