We found this circuit in the October 1996 Electronics Now magazine. The circuit uses LDRs as sensors and drives relays. The relays must have voltages according to the power supply.
We found this circuit that uses a thermistor as a sensor from the 1991 Electronics Experimenter Handbook....
This unusual output stage was found in the October 1974 issue of Radio Electronics magazine. The...
This circuit is from a 1998 Electronics Now and can be easily assembled since it uses a common...