Found in a 1967 American electronics magazine, this circuit has an input impedance of 2000 ohms. The circuit can be built with modern equivalent transistors.
This circuit for shunt motors was found in an American 1980s documentation. The SCR should be rated...
We found this circuit in an old documentation. Transistor can be BC548 and relay according to...
This circuit is based on the bistable configuration, but with the difference that the values of...