Portable Emergency Light cum Mobile Charger

Here is Portable Emergency Lamp cum Mobile charger. It uses a high bright White LED that can give sufficient light in the room when the mains power fails. It can be also used as a Mobile charger in the plug in mode as well during journey.

Power supply for the circuit is derived from a 0-6 volt 300 mA step-down transformer , a fullwave rectifier comprising D1 through D4 and the smoothing capacitor C1. The Emergency light circuit consists of diode D5, resistor R2 and the Transistor T1.When the mains power is available, diode D5 forward biases and the 6 volt battery charges through resistor R2.At the same time, the PNP transistor T1 will be out of conduction since its base is kept high through R1. The white LED connected to the collector of T1 remains off. When the mains power fails, D5 reverse biases and the base of T1 gets a negative bias and it conducts. White LED then turns on using the power from the battery.

The Mobile charger section of the circuit consists of a Zener based regulated power supply. Charging current can be tapped from the points A and B using suitable connector.

Assemble the circuit on a common PCB and enclose in a plug in type adapter box so that it can be plugged directly into the wall socket. Use a small 6 volt rechargeable battery to make the unit compact. Use a high bright White LED to get sufficient light

Categories: DIY PROJECTS