How Does a Voltmeter Work?
Voltmeter measure the voltage difference between two places, such as two points within a circuit . The typical voltmeter has two terminals, connected to wires or "leads." Place the tip of one lead at one of the points to be tested and the tip of the other at the other point, and the meter shows you the difference.
People use the word "voltage" all the time without really understanding it. Voltage is not current -- that is, it's not the flow of electrons from Point A to Point B. Rather, it's a measure of the ability to deliver an electric charge from Point A and Point B. Think of it like a fire hose: Current is the water flowing through the hose, while voltage is the pressure behind the water that causes it to flow. If there's no voltage, there will be no current. Voltage is by definition a measure of difference: the difference in electric potential between Points A and B. That's what the voltmeter measures.
In an analog voltmeter, each lead
http://en.wikipedia.org/wiki/Voltmeter http://www.reprise.com/host/electricity/voltage.asp http://amasci.com/miscon/voltage.html http://www.facstaff.bucknell.edu/mastascu/elessonshtml/measurements/measvolt.html
Ann Johnson has been a freelance writer since 1995. She previously served as the editor of a community magazine in Southern California and was also an active real-estate agent, specializing in commercial and residential properties. She has a Bachelor of Arts in communications from California State University, Fullerton.