The Whirlpool microwave diode converts the alternating current (AC) power output of the transformer to direct current (DC), doubling the voltage to nearly 5,000 volts. It is a device that ensures power flows in one direction and not the other. This high voltage powers the magnetron to heat the food or beverage placed in the oven cavity. Defective diodes will usually emit an electrical burning smell, signifying their defect.