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.
This circuit, from an old ON Semiconductor publication, suggests a shield to excite an LED from an...
In the figure we have a security system consisting of a sophisticated alarm found in a 90s edition...
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...