This transmitter circuit operates in shortwave HF band (6 MHz to15 MHz), and can be used for shortrange communication and for educational purposes. The circuit...

This over/under voltage cut-out will save your costly electrical and electronic appliances from the adverse effects of very high and very low mains voltages. The...

The circuit of a 7MHz C W / A M QRP transmitter described here can be used to transmit either CW or audio frequency...

The circuit described here can be used for controlling a decorative lamp from zero intensity to maximum intensity in a specified time. Typical applications...

This temperature switch has high sensitivity and is quite reliable. Here, in place of a single transistor, a Darlington pair has been used for...

Here’s a clap switch free from false triggering. To turn on/off any appliance, you just have to clap twice. The circuit changes its output...

The circuit presented here can be used for connecting two tele phones in parallel and also as a 2-line intercom. Usually a single telephone is...

The circuit as shown in the figure employs 14 bi-colour (red and green) LEDs having three terminals each. Different dancing colour patterns are produced...

Many a times one needs an extra telephone ringer in an adjoining room to know if there is an incoming call. For example, if...

Here’s a circuit to display the song number in an audio system for quick reference to songs. It also serves the purpose of an...