This circuit allows control of loads of up to 1 A with voltages from 3 to 15 V. The transistor must be equipped with a heat sink and the power supply must not be of the type without a transformer.
Today we have more compact solutions. This is from a Radio Electronics magazine from October 1990....
This filter was found in Texas Instruments documentation from the 1980s. The circuit uses a common...
16 commercial test circuit for tubes and transistors appeared in Radio Electronics magazine in...