This circuit was found in the Electronics Experimenter Handbook from 1991. The sensor is a diode and the circuit has a relay according to the voltage used in the supply.
This circuit was obtained in an Electronics Now of the 90s. The circuit monitors the DIN connector of...
Found in a 1965 Motorola documentation, this circuit uses a neon lamp as a trigger element. The SCR...
The outputs of each switch position are determined by the zener voltage plus the drive voltage of each...