Using 5 V relays, this circuit can be used as a control shield for microcontrollers. The circuit uses relays, and the motor voltage is independent of the control voltage.
This voltage calibrator circuit using a zener diode was found in Radio Electronics magazine from...
The relay of this circuit closes when the position set in P2 is reached by the sensor...
The purpose of this circuit, which we find in an old American documentation, is to allow the...