Inductors are typically used as energy storage devices in switched-mode power devices to produce DC current. The inductor, which stores energy, supplies energy to the circuit to maintain current flow during “off” switching periods, thus enabling topographies where output voltage exceeds input voltage.
Due to the way they work—by not only altering electric field but the magnetic field around it—many people struggle to understand them.http://www.goldcoil.net/inductor/