We obtained this circuit in a technical documentation from the 90's. The circuit has its sensitivity adjustment in the potentiometer. The supply voltage can be reduced with a 1k resistor change.
This circuit increases the sensitivity of a multimeter in the measure of small alternating...
This circuit triggers a buzzer or other warning device when the light falling on the sensor is cut...
This circuit open and close the relay in intervals adjusted by the potentiometers. The capacitors...