How can the GT200 operate without any external power source?
Electro-static electricity is very much misunderstood. The GT200 does not require power in order to operate. It requires a very high level of electric current but without amperage. This is why it cannot be mounted in a stationary position to operate. The production of power is generated by the movement of the operator. As the operator walks the perimeter of the defined search area, he (or she) is generating elector-static electricity. As one moves, you can generate power which, at times can be in excess of 2,500-3,000 volts! This in turns power the GT200. The GT200 becomes active and starts to receive signals from the magnetic signature of the targeted substance.