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 variable oscillator with power step for alarms was found in an American documentation from...
This circuit was found in a 90s Radio Electronics. It produces an ultrasonic signal in a special...
This circuit is only used for resistive loads such as incandescent lamps. The bridge diodes can be...