These optical relays, which can act as a shield, were found in an American documentation from the 1980s. The circuit has a LDR sensor. It can be adapted for other types of sensors.
We found this circuit in the April 1975 Radio Electronics magazine. The circuit has a latch and...
We found this sophisticated home alarm in a 1994 documentation. The circuit supports sensors of...
This circuit was found in the 1991 Electronics Experimenter's Handbook. It activates a relay when...