A voltmeter is an instrument used to measure the voltage between two points in an electrical circuit. Some voltmeters register direct current while others measure alternating current.
There are two basic types of voltmeters: analog and digital, with digital being the more accurate of the two. An analog voltmeter is built with a galvanometer in series with a high resistance and the inter resistance of the voltmeter must be high. A digital voltmeter shows the voltage as numbers.
Voltmeters are used in a variety of different industries. They are common in laboratories and the automotive industry, and home electricians use them every day.