Found in Radio Electronics from May 1959, this transistor tester is quite sophisticated. The circuit uses a 1 mA analog indicator.
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...