Capacitors, Magnetic Circuits, and Transformers is a free introductory textbook on the physics of capacitors, coils, and transformers. See the editorial for more information....

Electrical Energy

Electrical energy results from forces between electric charges, from the motion of electric charges, and from both forces and motion associated with electric charges. Electrical energy may be stored in the electrostatic field. This occurs in capacitors where there is an accumulation of positive charges on one plate and an accumulation of an equal number of negative charges on the other plate. Such stored energy is potential energy because it results from the position of positive charges relative to negative charges giving rise to forces between the plates of the capacitor. Electrical energy may also be stored in the magnetic field, in which case electric charges in motion (current) produce a magnetic flux. This is a case of kinetic energy because it results from charges in motion.

Electric storage batteries and dry cells do not store electricity. Their operation depends upon energy conversion. During discharge, chemical energy is converted to electrical energy. In charging a storage battery the reverse process occurs, in that electrical energy is converted into chemical energy. Nuclear reactions that give rise to the transformation of mass to energy result in nuclear energy.

Last Update: 2011-02-16