<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (December 2016) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (December 2016) (Learn how and when to remove this template message) </Td> </Tr> <P> The wattmeter is an instrument for measuring the electric power (or the supply rate of electrical energy) in watts of any given circuit . Electromagnetic wattmeters are used for measurement of utility frequency and audio frequency power; other types are required for radio frequency measurements . </P> <P> The traditional analog wattmeter is an electrodynamic instrument . The device consists of a pair of fixed coils, known as current coils, and a movable coil known as the potential coil . </P>

What type of power does a wattmeter measure