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 circuit was found in the Optoelctronics Sourcebook from Texas Instruments. The circuit has a...
We found this circuit with duty cycle adjustment in the May 1988 Radio Electronics magazine. The...
This 2.5 A power supply was found in a 90's QST magazine. The power transistor must be mounted on a...