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.
Mouser Electronics is now shipping DA14585, a kit for the development of voice remote control...
This circuit consists of a low-pass filter for the frequency of 440 Hz. The filter therefore...
This circuit is from an American documentation from 1976. The FET can be the BF245 or MPF102 and...