Found in an American publication from 1968, this circuit aims to keep the torque of a DC motor constant. The power transistor depends on the motor.
This series sensor circuit is from 1995 Popular Electronics. The circuit can use any SCR and the...
The circuit is a multivibrator version using two NPN general purpose transistor. This circuit can...
This circuit is from 1976 documentation. It uses the operational amplifier 709 which is no longer...