This control for 12 V drills was found in a 90s Elektor. The components are current, and Q1 can be replaced by a TIP42 mounted on a heat radiator.
This circuit is from 1950, from the time when some still called the crystal triode transistor. The circuit is...
In the circuit shown in the figure, when the input voltage rises to 27 V, the TL431 triggers the...
This circuit was found in a Popular Electronics from the 90s. The power source must be symmetrical...