Electronics Components: Put Inductors to Work

By Doug Lowe

If you have been wondering what inductors are actually used for in real-life electronic circuits, here are a few of the more common uses for inductors:

  • Smoothing voltage in a power supply: The final stage of a typical power supply circuit that converts 120 VAC household current to a useable direct current is often a filter circuit that removes any residual irregularities in the voltage due to the fact that it was derived from a 60 Hz AC input.

  • Filter: Selects frequencies that should be allowed to pass, or it selects frequencies that should be blocked. You’re probably familiar with the tone settings on a stereo system, which let you bump up the bass, tone down the midrange, and may ease up the upper range just for brightness.

    There are three different types of filters: high-pass filters which allow only frequencies above a certain value to pass, low-pass filters which allow only frequencies below a certain value to pass, and band-pass filters which allow only frequencies that fall between an upper and a lower value to pass.

  • Radio tuning circuits: Coils can be used to help a radio tuning circuit tune to a particular frequency signal and hold it.

  • Transformers: One of the most common uses of inductors is in transformers. The simplest transformer consists of a pair of inductors placed next to each other. The transformer serves two functions. First, it can increase or decrease voltage, and second, it can electrically isolate one part of a circuit from another.