Electromotive force, also called
emf (denoted
![](http://info.babylon.com/onlinebox.cgi?rt=GetFile&uri=!!ARV6FUJ2JP&type=0&index=3789)
and measured in
volt), is the voltage developed by any source of electrical energy such as a
battery or
dynamo. It is generally defined as the electrical potential for a source in a circuit. A device that supplies electrical energy is called a seat of electromotive force or
emf. Emfs convert chemical, mechanical, and other forms of energy into electrical energy. The product of such a device is also known as
emf.