The joule (pronounced DJOOL) is the standard unit of energy in electronics and general scientific applications. One joule is defined as the amount of energy exerted when a force of one newton is applied over a displacement of one meter. One joule is the equivalent of one watt of power radiated or dissipated for one second.
In some applications, the British thermal unit (Btu) is used to express energy. One Btu is equivalent to approximately 1055 joules.