This anti-theft circuit was found in a 1985 documentation. It uses common components that can still be found easily. The relay is 12 V and the circuit has timings of 3 minutes and 20 seconds.
July 2017 - Microchip's new MCP9V91 operational amplifiers with input offset and low drift voltage...
When the sensor, an ordinary photo-transistor, receives light, the relay closes its contacts. The...
Found in a 1964 Electronic Design, this circuit suppresses arcs that occur in contacts when a...