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.
This amplifier for automotive use was found in the SGS manual of linear integrated circuits of...
This circuit was found in documentation from the 70s. We can try current JFET transistors....
This circuit makes use of a thermometric sensor that heats or cools according to a current of air....