This light activated relay circuit presented here uses the 555 timer IC and a light dependent resistor or LDR to form a light sensitive relay in an intruder alarm system or for switching on a lamp at ...

This light sensor switch circuit allows the automatic connection of a lamp when the light is low (at nightfall) and will maintain the lamp ON for a certain period of time. This time can be adjusted ...

Relays usually are driven using optocouplers, which offer isolation between analog and digital grounds to ensure that switching currents in the relay coils do not affect the noise margin of the ...

Last column, I wrote about various applications where fire alarm relays could be used to integrate a commercial fire alarm system with other electrical systems at a customer’s site to provide them ...