A good number of circuits which turn off the power to the load on mains failure have already appeared in EFY. This circuit is...

During summer nights, the temperature is initially quite high. As time passes, the temperature starts dropping. Also, after a person falls asleep, the metabolic...

PROBIR GOYAL Here is a simple technique for measuring frequencies over quite a wide frequency range and with acceptable accuracy limits using a PC. It...

Anormal priority encoder encodes only the highest-order data line. But in many situations, not only the highest but the second-highest priority information is also...

This circuit can control any one out of 16 devices with the help of two push-to-on switches. An up/down counter acts as a master-controller...

The circuit given here can be used to send telegraphic messages via computer. The message data entered through the computer keyboard is converted to...

Cordless telephones are very popular nowadays. But they have a major drawback, i.e. they cannot be operated during power failure. Therefore usually another ordinary...

Most of the telephone security devices available in market are simple but quite expensive. These devices provide blinking or beeping type line-tap misuse indications....

This intelligent switch circuit enables automatic, switching on of an emergency light system during darkness in the event of mains failure. The mains power...

A high voltage power supply is a very useful source which can be effectively used in many applications like biasing of gas-discharge tubes and...