Inductors can be divided into three main categories: power supply switching regulator, EMC noise suppression, and high frequency matching. Power supply inductors are used for smoothing output voltage within DC/DC converters. EMC inductors can be used to filter electromagnetic (EM) waves in conjunction with a capacitor or another inductor to prevent interference with other circuit blocks. They can also be used to counter the effects of radiated noise which is an unwanted EM wave derived from other blocks that may cause ICs to malfunction. Lastly, high-frequency inductors are used for matching RF circuit blocks with other blocks.