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a b
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alternating
current current that reverses its direction of 

ambient air temperature
the temperature of the surrounding 

American Wire Gauge (AWG)
an English standard for 

ammeter a device for measuring current flow 

ammeter shunt a device that allows an ammeter to measure 

amp a measure of electric current defined as one coulomb
per second 

ampacity the amount of current that a wire can carry 

amplitude the maximum height reached by a waveform 

analog meters meters that employ a moving pointer to indicate 

angle theta (_u) the phase angle difference
between voltage and current in a circuit
containing a reactive component 

apparent power (VA) the value found by multiplying the applied voltage by the total
current of an AC circuit. Apparent 

apparent power volt amps
(VA) the product of the total 

appear to flow the charging and discharging of a capacitor 

artificial respiration a method of providing oxygen to a person unable to breath on
his or her own 

atom the smallest part of an element, atoms are composed 

atomic number the number of protons located in the nucleus of an atom 

attraction generally the force that exists between objects 

autotransformer a transformer that uses only one winding 

average the value of voltage when an AC sine wave voltage 

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bidirectional
a device that can conduct current in either 

British thermal unit (BTU)
the amount of heat necessary 

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capacitive
reactance (Xc) the currentlimiting effect of a capacitor 

carbon film resistor a resistor made by coating a nonconducting 

centrifugal force the force that causes a spinning object 

centrifugal switch a switch used to disconnect the start 

chassis ground a conductor connected to the metal case 

circuit branch (a) in the case of parallel circuits, a circuit 

circuit breakers devices that disconnect power to a circuit 

circular mil an English measure for determining the crosssectional 

clampon ammeter an ammeter with a movable jaw that 

color code a method of marking the resistance and tolerance
of a resistor with bands of
color 

combination circuit a circuit that contains both series and parallel circuits 

compensating winding a winding used in universal motors to counteract the inductive
reactance in the armature windings 

complete path an electric circuit that exists from the more negative to the more
positive voltage 

composition carbon resistor
a resistor that is made by 

conductive compensation
accomplished by connecting 

conductors materials that conduct electricity easily 

confined space a space that has limited entrances or exits 

control transformer a common type of transformer used 

conventional current flow
theory an older theory stating 

correction factor a decimal fraction employed to determine 

coulomb a quantity measure of electrons that equals electrons 

CPR an acronym for cardiopulmonary resuscitation 

current adds one of the three rules used to solve values of 

current divider formula
a formula used to calculate the 

current flow through the
inductor (IL) the amount of 

current lags voltage the relationship of current and voltage 

current transformer a transformer used to measure large 

cycle one cycle is completed when an AC voltage completes 

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d’Arsonval
movement a galvanometer that employs a 

damp location a location that is covered and not likely to 

deenergized circuit a circuit that has been disconnected 

dielectric the insulation between the plates of a capacitor 

dielectric stress the stretching of the molecular structure of the dielectric 

direct current (DC) current that flows in only one direction 

disconnect to turn off or remove power from a circuit 

distribution transformer
a transformer that is generally 

dry location a location that is not normally subject to dampness or wetness 

earth ground
point at which a metal rod is driven into the 

eddy current electric currents induced in metal; generally 

egress an entrance or exit into a structure 

electrolytic a type of capacitor that is polarity sensitive 

electromotive force (EMF)
the force known as voltage 

electron orbit the space in which an electron circles the 

electron theory the theory stating that electricity flows from the more negative power
source to the more positive 

electron a sub atomic particle that orbits the nucleus of
an 

electrostatic charge the charge of a capacitor produced 

element a material, the smallest part of which would be
an 

energized circuit a circuit connected to the power supply; 

excitation current the amount of current that flows in the 

exponential the rate at which a capacitor charges and discharges 

exponential curve a rate at which current increases or decreases 

fibrillation a condition in which the heart starts to quiver and stops its pumping action 

fire retardant clothing
clothing made from a specially treated material that resists
ignition; many industries require 

flux leakage the amount of magnetic flux lines that radiate 

frequency the number of complete cycles that occur in one 

frequency the number of times per second that the current 

fuses devices that disconnect power to a circuit in the event of an excessive amount
of current 

galvanometers
very sensitive meters that require only a 

general voltage divider
formula a formula employed to 

ground point point at which a circuit or device is grounded 

grounding conductor generally the bare or green wire 

hertz a measure of frequency 

HIPOT an instrument that develops a high potential or
high 

Holtz motor a type of singlephase synchronous 

horseplay playing practical jokes or exhibiting adolescent 

horsepower a common measure of power in which the base 

hysteresis loss the amount of power loss in the form of heat caused by molecular friction 

idiot proofing
designing a piece of equipment so it cannot 

impedance the total current limiting effect in an electric circuit; impedance is measured
in ohms. 

impedance (Z) the total currentlimiting effect in an AC circuit 

in phase a condition that occurs when the voltage and current 

induced voltage voltage that is supplied to a conductor by cutting lines of magnetic
flux 

inductance (L) the property of an electric circuit whereby 

inductive compensation accomplished by shorting the 

inductive reactance (XL) the currentlimiting effect of a 

inrush current the amount of current flow that occurs when power is first applied
to a transformer 

insulation the plastic or rubber coating around the conductor 

insulators materials that hinder the flow of electricity 

isolation transformers transformers that have their primary 

joule a metric measure of power similar to the English 

laminated
the process of stacking thin sheets of metal together 

leakage current the amount of current that flows through 

Lenz’s law an electrical law stated by a scientist named Lenz that says, basically,
that an induced voltage will always 

linear wave a waveform that increases in the same proportion 

load the amount of power a circuit is supplying to a
device 

lock out and tag out a procedure to prevent a circuit from being energized accidentally 

magnetic
induction using magnetic field to induce a voltage 

matter any material composed of atoms 

maximum operating temperature
the maximum temperature 

MEGGER® a device used to measure the
insulation resistance; 

metal film resistor a resistor made by coating a nonconducting 

metal glaze resistor a resistor made by combining glass 

metal oxide varistor (MOV)
an electronic device that
exhibits 

meter an instrument used to test for some electrical
quantity 

mil foot an English standard of measure for wire; a mil
foot 

milliamperes one milliampere equals 1/1000 of an amp (0.001) 

molecules a combination of atoms that form the smallest 

MSDS an acronym for material safety data sheets 

multirange voltmeters voltmeters that employ more than 

multispeed motors motors designed to operate at more 

multiturn variable resistors
resistors constructed so that their ohmic value can
be adjusted by turning a shaft from three to ten turns 

National
Electrical Code a national standard for installation 

negative a charge formed by an excess of electrons 

neutral conductor a conductor is generally grounded and 

neutral conductor the part of an electric circuit that is generally grounded 

neutral plane the point at which no voltage is induced in 

neutron one of the principal parts of an atom. The neutron 

node a point of connection 

nonpolarized capacitors
capacitors that are not sensitive 

nucleus the center or core of an object 

ohm (V)
the unit of measure used to describe the resistance 

Ohm’s law a set of mathematical formulas developed by the German scientist Georg
S. Ohm 

ohmmeter a meter used to measure values of resistance 

oscillators devices used to convert direct current into alternating 

OSHA an acronym for Occupational Safety and Health Administration 

out of phase a condition that occurs between the voltage 

parallel
block a section of a combination circuit composed 

parallel circuits circuits with more than one path for current 

parallel conductors conductors connected in parallel with 

parallelogram method a method of obtaining values of 

peak the maximum value obtained by a waverform 

plates thin, flat metal used in the construction of a
capacitor 

polarized capacitors capacitors that are sensitive to voltage 

positive a charge formed by a lack of electrons 

pot slang for potentiometer 

potentiometer a variable resistor employed in such a manner that it can provide
a variable voltage 

power the ability to do work; in an electric circuit,
it is generally measured in watts 

power factor (PF) the ratio of true power to apparent power 

primary winding the winding of a transformer to which power is connected 

product over sum formula 

proton a subatomic particle located in the nucleus of
an 

quadrature
power often referred to as VARs, reactive 

quality (Q) the ratio of capacitive reactance to resistance 

quality (Q) the ratio of inductive reactance as compared with resistance 

RC time
constant the time required for a capacitor to charge 

reactance the property of a circuit that limits current by means other than resistance 

reactive power (VARs) volt amps reactive; often called 

reactive power (VARs) VoltAmps Reactive; often referred 

reciprocal formula 

reduce a method employed to simplify parallel or series connected components into
a single resistor 

repulsion generally the force that exists between two objects 

resistance the element of an electric circuit that can limit 

resistance adds one of the major rules concerning series 

resistive loads loads that employ resistance to limit circuit 

rheostat a variable resistor that contains only two terminals 

ripple the turning on and off effect that occurs when
alternating 

RL time constant the amount of time required for current 

root mean square (RMS) the amount of AC voltage that 

run winding one of the windings in a splitphase motor 

scaffold
a platform for working in high places, generally 

secondary winding the winding of a transformer to which 

series circuit a circuit that contains only one path for current 

series resistance resistance connected in series with other circuit components 

shadedpole induction motor
a singlephase motor that 

shading coil the loop of large wire used to form a shaded 

short circuit a circuit that contains almost no resistance to limit the flow of current 

sine wave a waveform produced by any rotating machine. 

skin effect the effect that causes electrons to move toward 

splitphase motor a type of singlephase motor that splits the current flow through
two separate windings to produce 

start winding one of the windings used in a splitphase motor 

stepdown transformer a transformer that produces a 

stepup transformer a transformer that produces a higher 

strength of magnetic field
the number of magnetic flux 

surface area one of the factors that determines the amount of capacitance a capacitor
will have 

synchronous motors motors that operate at a constant 

synchronous speed the speed of the rotating magnetic 

tape wound
core a type of transformer core made by roundedrectangle shape 

tolerance the range over which a resistor is considered to 

toroid core a transformer core that is in a toroid shape, which is generally round with
a hole in the center similar to 

total current (IT) the total current flow in an electric circuit 

total current (IT) the total current flow in an electric circuit; of the resistive current and
inductive current 

total impedance the total currentlimiting effect in an AC 

total impedance the total currentlimiting effect in an AC 

trace the current path a method used to determine if components are connected in
series or parallel 

transformer an electrical machine used to change values 

triangle wave a linear waveform in which the voltage is proportional 

true power the amount of electrical energy that is converted 

turns of wire the number of turns of wire on a coil 

turns ratio the ratio of the number of turns of wire in the 

two phase a power system that produces two separate phase voltages 90° apart 

universal motor a type of singlephase motor that can operate 

valence
electrons electrons located in the outermost orbit 

variable capacitors capacitors that can be adjusted for different values of capacitance 

variable resistor a resistor whose resistance value can be 

vector addition the process of using vectors to add like electrical values 

vector a line that indicates both magnitude and direction 

volt a measure of EMF often described as electrical
pressure 

voltage divider a circuit generally constructed of series connected resistors to provide
different amounts of voltage 

voltage divider a circuit used to provide different values 

voltage drop the amount of voltage employed to push current 

voltage drop the amount of voltage existing across any component that limits the
flow of current; voltage drop indicates through a limiting element 

voltage polarity the polarity, positive or negative, of the 

voltage rating the amount of voltage that can be safely applied to a capacitor without
damaging the dielectric 

voltage spike a large amount of voltage that exists for a 

voltmeter a meter used to measure voltage 

voltsperturn ratio a method of determining voltage values 

Warren motor
a type of singlephase synchronous motor 

watt a power measurement that describes the amount of 

wattless power VARs; computed by using values that pertain 

watts a measure of electric power 

watts the true power in a circuit; indicates the amount
of 

weber a measure of magnetism equal to 100,000,000 lines 

wet location areas that are subject to saturation by water; 

wire wound resistor a resistor made with a highresistance 

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