millivolt

A millivolt (mV) is a unit of electrical potential difference, equal to one-thousandth of a volt. While a volt is a substantial measure of electrical force—enough to power lights or run appliances—the millivolt represents an incredibly small voltage. It's not something you would directly experience as a shock, but it is crucial in many areas where the precise measurement of low-level electrical activity is needed.

The term comes from combining "milli-" (meaning one-thousandth) with "volt," which was named after the Italian physicist Alessandro Volta. You won't find millivolts powering your television, but you will find them at work in a surprising number of places.

In electronics, millivolts are used to measure the output of sensors and amplifiers, especially those dealing with weak signals. In biology, nerve impulses travel along neurons as changes in electrical potential measured in millivolts. Doctors use instruments that detect these tiny voltage fluctuations during tests like electrocardiograms (ECGs), which measure the heart's electrical activity, or electroencephalograms (EEGs), which measure brain waves.

Even in everyday life, you might encounter millivolts when troubleshooting a faulty battery or examining the performance of a low-voltage circuit. So, while it is small, the millivolt plays a big role in understanding and controlling the electrical world around us—from the technology we use to the very workings of our bodies.