Often it requires high voltage DC supply for different application. In presence of mains supply, high voltage DC is obtained quiet easy but it becomes quite difficult in case of battery. Circuit described here is quiet simple and is similar to an inverter. The circuit uses step up transformer for obtaining high voltage and rectifies it for obtaining high voltage DC.

The circuit is designed to produce 100-150 V DC from 6 V battery. The high voltage is obtained using center tapped transformer (not dangerous though it can inflict an unpleasant jolt). A 6.3 V transformer is connected "in reverse" with a transistor used in a Hartley oscillator configuration. The frequency of operation may be controlled by varying the value of the 10 K ohm resistor. The 10 µF capacitor must have a working voltage of at least 250 V dc.
 

   Schematic

;