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.
I got this circuit from an English magazine from 1977. It can still be easily assembled, as the...
The configuration shown allows to obtain a high voltage gain for FETs. FETs can be BF245 or...
This circuit controls a heating element using a triac. Triac must be fitted with a heat sink. We...