Using an LDR, this Philips circuit directly activates a relay when light strikes the sensor. The relay is 45 V with 20k coil resistance. The 220 nF capacitor must be polyester for 400 V.
We found this circuit in the June 1991 issue of Radio Electronics magazine. The circuit can be...
This precision circuit, which also functions as a bridge, was found in a February 1967 Popular...
We found this circuit in an old documentation from the 70s. The text is the original one of the...