This circuit is from a 1967 RCA publication. The components are of the time, admitting equivalents, including the SCR that determines the maximum power of the load.
This 1987 signal injector included the power supply from the power grid. The transformer is 6 + 6...
This amplifier was found in a 70s documentation. The product gain x bandwidth is 350 MHz. The...
This simple receiver with junction FET uses a high impedance magnetic earphone (over 2 k). Power...