This great little project demonstrates the principles of high frequency magnetic induction. The circuit is very simple to build and only uses a few common components. With the induction coil shown here the circuit draws about 5A from a 15V supply when a screwdriver tip is heated. It takes approximately 30 second for the tip of the screwdriver to become red hot!
The control circuit uses a method known as ZVS (zero voltage switching) to activate the transistors which allows for an efficient transfer of power. In the circuit you see here, the transistors barely get warm due to the ZVS method. Another great thing about this device is that it is a self resonant system and will automatically run at the resonant frequency of the attached coil and capacitor.