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.
Found in Radio Electronics this circuit uses a fotodiac to drive a triac. The circuit can use...
Based on components from Linear Technology, we find this circuit in a 2005 manual. The circuit...
Found in Popular Electronics from the 90s, this generator uses integrated circuits from that time....