Fibrillation – 

the potentially fatal unsynchronized heartbeat that may result from electric

shock.

Electrocution – 

a term combining the words electric and execution used to refer to fatal

electric shock.

Blowout – 

Arc Flash – 

the result of ionized air forming a conductive path between current carrying

conductors.

Arc Blast – 

explosive pressure resulting from the heat of an arc flashV-rated

One Hand Rule – 

a last resort practice of using only one hand while maintaining live

electrical or electronic equipment in the hopes of preventing an inability to separate from

the power source during electrical shock.

Lockout / Tagout – 

the procedure of securing and/or identifying a deactivated electrical

device during installation or maintenance.

Alternating Current – 

an electric current that reverses direction; may or may not change

periodically.

Sine Wave – 

a symmetrical periodically alternating current.

Complex Wave – 

Vpp – 

Volts-Peak-to-Peak; the amplitude of an alternating current as measured from one

peak to the opposite polarity peak.

Vp – 

Volts-Peak; the amplitude of an alternating current as measured from the midpoint

to the peak.

VRMS 

– Volts-Root-Mean-Square; implied unit of measure for alternating current that

allows a more accurate power comparison to DC than Vp or Vpp units. Also, the

mathematic process used to quantify a non-zero average representing an alternating

waveform

True RMS Meter – 

a meter that accurately measures RMS voltages for non-sinusoidal

waveforms.

Voltage Drop – 

Parasitic Resistance –

 unintended and unavoidable opposition to current flow of an

electrical conductor.

I2R Losses – 

Impedance – 

the opposition to the flow of alternating current; the vectorial summation of

resistance and reactance.

Reactance – 

the frequency dependent component of impedance; the difference of

inductive reactance and capacitive reactance.

Inductor – 

a conductive coil that opposes changes in the amount and direction of current

flow.

Inductive Reactance – 

the directly proportional frequency dependent opposition to

alternating current flow due to inductance; a component of impedance.

Capacitor – 

Capacitive Reactance –

the inversely proportional frequency dependent opposition to

alternating current flow due to capacitance; a component of impedance.

Phase Angle (Θ) – 

ELI the ICEman – 

a mnemonic used to describe the phase angles of current and voltage

for inductance and capacitance; in inductors (L), the current (I) lags the voltage (E) by up

to 90º; in capacitors (C), the voltage (E) lags the current (I) by up to 90º.

Power Factor – 

calculated as the cosine of the phase angle between voltage and current,

is the ratio of real power to apparent power. Is equal to or less than 1.

Phase (Φ) – 

for power configurations and conductors, refers to individual legs of power;

ex: 3Φ Power has 3 phases.

Real Power – 

the power actually consumed by the load.

Apparent Power – 

the vectorial summation of real power and reactive power, the

product of amps and volts; the amount of power that is apparently consumed by the load.

Volt-Amperes (VA) – 

the unit of measure for Apparent Power; the product of a peak

current of 1 amp and a peak voltage of 1 volt.

Reactive Power – 

Volt-Amperes Reactive (VAR) – 

Power Factor Correction – 

the use of capacitance or inductance to raise power factor

for inductive of capacitive loads.

Circuit Ground – 

the zero volt reference and unbalanced signal return path for current

located on a Printed Circuit Board (PCB).

Signal Ground – 

the zero volt reference and unbalanced signal return path for current

located in a signal cable; often connects circuit grounds between devices and therefore

may be lifted at the receiving gear input to prevent unintentional ground currents from

flowing.

Common Ground – 

an unreliable term that could mean just about anything; including

neutral, circuit ground, chassis ground, 3-way switch hot wire, and mutual life experience

allowing groups of (2) or more people to relate on some level.

Chassis Ground – 

the grounded metal case of a device used for shielding the circuit

within; the most exposed part of a grounding system and therefore often connected to

Earth ground.

Earth Ground – 

a local electrical connection to the Earth used for lightning protection

and as a zero volt reference.

Simple Circuit – 

the most basic requirements for current flow consisting of a Source, a

Load, and a Closed Path.

Earth Grounding System – 

a grounding system consisting of a grounding electrode,

grounding conductors, and a bonding location.

Grounding Electrode – 

an electrical conductor used to create an electrical connection to

the earth

Grounding Conductors – 

non-current carrying conductors routed with the supply

conductors to provide a low impedance return path for fault currents and distribute the

zero volt reference.

Bonding Location – 

the single point on the load side of a power source where the local

earth ground (grounding conductor) and neutral (grounded conductor) are bonded

together to complete a local zero volt reference for power and a return path for fault

currents.

Ground Loop – 

a closed path within a grounding system.

Ground Noise Current – 

Fault Current – 

any current flowing on an unintended return path.

Capacitive Coupling – 

the transfer of electrical energy across an insulator as an electric

field.

Parasitic Capacitance – 

unintended capacitance between power conductors and a return

path for current; a potential source of ground current.

Buzz- 

capacitively coupled system noise, typically rich in high order harmonics of 50-

60Hz.

Inductive Coupling – 

the transfer of electrical energy across an insulator as a magnetic

field.

Parasitic Transformer – 

unintended inductive coupling between power conductors and

other conductive materials; a potential source of ground current.

Hum- 

magnetically coupled system noise, typically from a low frequency source.

Unbalanced Signal – 

an audio signal transmission method employing one hot conductor

for the signal and one ground conductor that serves as both a shield and a return path for

current, therefore creating an unequal impedance to ground from each signal carrying

conductor.

Common Impedance Coupling – 

the addition of noise to an audio signal resulting from

the voltage drop of a ground current flowing though a resistive path.

Pin 1 Problem – 

a phrase attributed to Neil Muncy, identifies a manufacturing defect in

some audio equipment with balanced interfaces that allows ground currents to flow

through the audio circuitry and be coupled as noise into the audio signal.

Hummer – 

a test device used to expose Pin 1 Problems in audio equipment by creating

current flow across circuit ground and chassis ground.

Balanced Signal – 

an audio signal transmission method employing two ungrounded

conductors of equal impedance to ground allowing the apparent cancellation of common

mode noise.

Differential Mode – 

an amplitude that is different across both signal conductors.

Common Mode – 

Common Mode Noise – 

Common Mode Rejection – 

the apparent cancelling of identical voltages by a

differential input.

Common Mode Rejection Ratio – 

the ratio of differential gain to common mode gain; a

measure of a differential input’s ability to reject common mode noise.

SCIN – 

Shield Current Induced Noise; noise inductively coupled into signal carrying

conductors by currents flowing in the cable shield.

Dummy Plug – 

an electronic termination device used for troubleshooting noise in audio

and video systems.

Star Ground – 

a grounding topology utilizing a central ground point to which all

grounded circuits and devices are connected.

Telescoping Ground – 

a grounding topology utilizing a single path to the ground origin,

often resulting in a ground path through interconnected equipment.

Isolated Ground Receptacle – 

a power receptacle used to separate its insulated

grounding conductor from all other grounded devices and materials.

Hybrid Ground – 

a capacitively coupled signal ground connection at a device input used

to filter ground currents by blocking low frequency currents and passing higher frequency

currents.

Ground Lift Cable – 

a balanced signal carrying cable used to separate the chassis

grounds of interconnected equipment by connecting the ground contact at only one end of

the cable; preferably connected at the sending equipment and “lifted” at the receiving

equipment.

Ground Lift Switch – 

a switch used at the balanced output of some audio equipment to

separate the chassis ground from interconnected equipment by “lifting” the ground

connection.

Ground Isolator – 

an active or passive signal carrying termination device used to

separate the chassis grounds of interconnected equipment.

Ground Lift Adapter – 

a fictitious device used to create potentially fatal audio

installations in the hope of reducing system noise. Properly used as a “3 to 2 prong

ground adapter” with the earth ground securely connected and having no beneficial effect

on system noise.

Harmonic Distortion - 

Transients - 

an extremely short spike in power source voltage

Surges- 

a momentary increase in power source voltage lasting less than one minute

Over Voltage - 

Sag- 

Under Voltage -  

long term decrease in power source voltage lasting more than one minute

Outage -