A power diode is a two terminal, anode a and cathode K and two layer P and N junction devices. A PN junction normally formed by allowing diffusion and epitaxial growth structure of a power diode. Basic structure and symbol of power of a power diode have larger power voltage and diode are shown in figure 1.1 power diodes have larger power voltage and current handling capabilities than ordinary signal diodes. In additions the switching frequencies of power diodes are low as compared to signal diodes. Some applications of these devices are electric traction, battery charging electro plating electro metal processing power supplies welding Ups etc.
figure Power diode (a) basic structure (b) Symbol