voltage

voltage
    n 1: the rate at which energy is drawn from a source that
         produces a flow of electricity in a circuit; expressed in
         volts [syn: {voltage}, {electromotive force}, {emf}]
    2: the difference in electrical charge between two points in a
       circuit expressed in volts [syn: {electric potential},
       {potential}, {potential difference}, {potential drop},
       {voltage}]
    

Voltage \Vol"tage\, n. (Elec.)
   Electric potential or potential difference, expressed in
   volts.
   [1913 Webster]
    

voltage
potential difference

   <electronics> (Or "potential difference", "electro-motive
   force" (EMF)) A quantity measured as a signed difference
   between two points in an electrical circuit which, when
   divided by the {resistance} in {Ohms} between those points,
   gives the current flowing between those points in {Amperes},
   according to {Ohm's Law}.  Voltage is expressed as a signed
   number of Volts (V).  The voltage gradient in Volts per metre
   is proportional to the force on a charge.

   Voltages are often given relative to "earth" or "ground" which
   is taken to be at zero Volts.  A circuit's earth may or may
   not be electrically connected to the actual earth.

   The voltage between two points is also given by the charge
   present between those points in {Coulombs} divided by the
   {capacitance} in {Farads}.  The capacitance in turn depends on
   the {dielectric constant} of the insulators present.

   Yet another law gives the voltage across a piece of circuit as
   its {inductance} in {Henries} multiplied by the rate of change
   of current flow through it in Amperes per second.

   A simple analogy likens voltage to the pressure of water in a
   pipe.  Current is likened to the amount of water (charge)
   flowing per unit time.

   (1995-12-04)