This transistor gain test was published in Radio Electronics magazine in July 1959. The transformer used is a special type common at the time. The circuit tests general-purpose transistors.
Found in an EDN from the 90's, this circuit can be implemented with modern operational amplifiers....
The two power steps below are intended for use with the SAA1027 stepper motor control but can be...
Indicated for discriminators adjustment in FM and VHF receivers, this circuit was found in a 90s...