electronics (Or "potential difference", "electro-motive
force" (EMF)) A quantity measured as a signed difference
between two points in an electrical circuit which, when
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
Yet another law gives the voltage across a piece of circuit as
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)