Voltage: Difference between revisions
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'''Voltage, electromotive force, or potential difference''' is the difference in electrical potential between the positive and negative poles of a battery or other device that generates a flow of electrons. The units of electrical potential in the [[SI]] and most other systems of units are [[volt]]s. | '''Voltage, electromotive force, or potential difference''' is the difference in electrical potential between the positive and negative poles of a battery or other device that generates a flow of electrons. Electrical potential is [[energy]] divided by [[electric charge|charge]], or energy per unit of electric charge. Since the [[joule]] is a unit of energy and the [[coulomb]] is a unit of electric charge, the joule per coulomb is a unit of electromotive force or of potential difference. A '''volt''' is a joule per coulomb. The units of electrical potential in the [[SI]] and most other systems of units are [[volt]]s. | ||
Electrical potential difference can be analogized by comparing to gravitational potential difference, the difference in potential energy per unit of mass between two objects at different elevations in a gravitational field. It can also, perhaps more usefully, be compared to pressure differences in hydraulic systems, with current flow analogized as the quantity of water flow, resistance as the size and roughness of the pipe or channel. | Electrical potential difference can be analogized by comparing to gravitational potential difference, the difference in potential energy per unit of mass between two objects at different elevations in a gravitational field. It can also, perhaps more usefully, be compared to pressure differences in hydraulic systems, with current flow analogized as the quantity of water flow, resistance as the size and roughness of the pipe or channel. | ||
Revision as of 19:17, 3 August 2007
Voltage, electromotive force, or potential difference is the difference in electrical potential between the positive and negative poles of a battery or other device that generates a flow of electrons. Electrical potential is energy divided by charge, or energy per unit of electric charge. Since the joule is a unit of energy and the coulomb is a unit of electric charge, the joule per coulomb is a unit of electromotive force or of potential difference. A volt is a joule per coulomb. The units of electrical potential in the SI and most other systems of units are volts.
Electrical potential difference can be analogized by comparing to gravitational potential difference, the difference in potential energy per unit of mass between two objects at different elevations in a gravitational field. It can also, perhaps more usefully, be compared to pressure differences in hydraulic systems, with current flow analogized as the quantity of water flow, resistance as the size and roughness of the pipe or channel.