This circuit appeared in Amateur Radio Today in an issue and was found in a 1995 issue. The circuit is for the AM band up to 3 MHz. The transistors are general-purpose.
Quadrature Generator for Transistor and SCR Testing This circuit was found in US 1980s...
This circuit, with output currents up to 500 mA, can stabilize or regulate the output voltage of a...
This circuit that uses only transistors that are still common was found in a 1995 documentation. The TIP41...