Glossary of Electrical Terms
Electricity has been in existence since the beginning of time. Over two thousand years ago the Greeks discovered static electricity by rubbing an amber fossil with a cloth. They believed the amber fossils were living stones and called them "elekton".
Alternating Current (AC): Electron flow that reverses polarity and direction of travel through a circuit. The common example is 60-cycle AC power, used in most homes and offices (USA), where voltage polarity and current go through 60 cycles per second.
Direct Current (DC): A type of electrical current and distribution by which electricity flows in one direction through the conductor. Battery operated systems are typical DC applications.
Electrical Formulas (Ohm's Law):
Voltage (E): Measure of pressure (electromotive force) in the conductor.
Volts = amps x resistance (E = I x R)
Watts (P): Measure of power used by an electrical circuit.
Watts = volts x amps (P = E x I)
Amps (I): Measure of rate of current (electron) flow.
Amps = volts ÷ resistance (I = E ÷ R)
Ohms (R): Unit of electrical resistance (opposition to flow of current).
Ohms = volts ÷ amps (R = E ÷ I)
Frequency: The number of times per second that an alternating current system reverses from positive to negative and back, expressed in hertz (Hz).
Hertz (Hz): A unit of frequency equal to one cycle per second. The USA standard is 60 hz.
Inrush Current: The current generated during the initial start up of a lamp system. Inrush current can be several times higher than the operating current.
Kilowatt (kW): A measure of electrical power equal to 1000 watts
Kilowatt Hour (kW/hr): 1000 watts of electricity used for one hour. A unit of measure that utility companies utilize for billing purposes.
Operating Current: Steady state current consumed by a lamp at rated watts.
Power Factor (PF): A measure of the effectiveness of which an electrical device converts amperes to watts. A high power factor means that an electrical system is utilizing power efficiently.
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