This is the simplest way to protect your valuable electronic equipment like, Telephone, Set top box, Modem, Router etc from Lightening damage. It instantly bleeds the excessive current flowing through the cables during a lightning discharge. It uses only two components, a TVS diode and an MOV and its cost is just Rs.20. Hook it in the feeder cable going to the equipment and stay relaxed.
You need the following components
1. TVS Diode PK6 12A – 1
2. MOV 431 K 1KV – 1
3. 2 Amps DC fuse – 1
4. Fuse Holder – 1
5. DC Jack and Socket pair – 2
How it works?
TVS (Transient Voltage Suppressor) diode P6KE 12A and MOV are doing the trick to protect the equipment. TVS diode is a special kind of diode that conducts current when its pn junction breaks down as a result of a heavy current flow. It is rated 600 watts. TVS Diode operates by shunting excess current when the induced voltage exceeds the Avalanche breakdown potential . It works like a Clamping device, suppressing all over voltage above its rated breakdown voltage. When the transients are over, the diode reset back to its normal position.
MOV is the Metal Oxide Varistor, a kind of passive component that varies the resistance with the applied voltage. It is also known as Voltage Dependent Resistor (VDR) and has electrical characteristics similar to a diode. At low voltage, it has high resistance and low resistance at high voltage. Unlike the diode, it conducts in both the directions. MOV contains a Ceramic mass of Zinc Oxide grains in a matrix of other metal oxides such as Bismuth, Cobalt, Manganese etc sandwiched between two metal plates ( Electrodes ). The boundary between each grain and its neighbour forms a diode junction, which allows current to flow in only one direction. When a small or moderate voltage is applied across the electrodes, only tiny current flows by reverse leakage. But when a large voltage is applied, the pn junction breaks through Thermionic emission and Electron tunneling and a large current flows.
When the high voltage as high as 1KV or higher strikes the cable, both TVS diode and MOV conducts and bleeds the high voltage. This creates a shorting between the lines and the fuse blows. This action takes place within Micro or even Nano seconds time. There is no need for replacing the TVS diode and MOV since they returns to normal after bleeding the current. Only the Fuse needs replacement.