Electricity

July 2004

Voltage

Voltage is a measure of electrical pressure. Think of it of the force of the electricity (commonly called Electromotive Force). It is also the difference in potential between two charged plates, or potential difference.

Units	Definition	Symbol
Volts (V)	One volt is the electromotive force required to drive one coulomb of electrical charge (6.24 x 1018)past a specific point in one second.	E or V

Current (Amperage)

Current is the rate of flow of the electricity.

Units	Definition	Symbol
Amps (A)	One Ampere of current is one coulomb of electrical charge (6.24 x 1018) moving past a specific point in one second.	I

Resistance

Opposition to the flow of electric current.

Units	Definition	Symbol
Ohm (W)	One ohm is when a current of one amp passes through a device in which has a potential difference of one volt.	R

Ohm's Law for Direct Current

The relationship between resistance, voltage and current.

Formulas

E = I R I = E /R R = E / I

Power

The rate at which electricity is produced or consumed. It is the amount of electricity required to operate a load for one second.

Units	Definition	Symbol	Formula
Watts (W)	One Watt is the amount of electricity consumed by a load which take one amp of current and a potential difference of one volt.	P	P = V * A

Electrical Energy

The amount of electricity used in a given time period.

Units	Definition	Symbol	Formula
Joules (J) or Watt-hours(Wh)	One joule of electrical energy is equal to one Watt of electricity consumed in one second. One Watt-hour of electrical energy is equal to one Watt of electricity consumed in one hour.	E	E = P t

One Watt-hour is equal to 3600 Joules.

Wire Size