This circuit was designed to detect when a call is incoming in a cellular phone (even when the calling tone of the device is switched-off) by means of a flashing LED. The device must be placed a few ...

Alarm system designs often require circuitry that can detect whether a phone line is active or broken. With this type of design, the primary difficulty is drawing less than 5 µA from the phone line ...

This is a simple circuit diagram of USB Mobile phone charger circuit which is more useful to charge your cell phone even when you are in travel. Now the charging of your mobiles has been made easy ...