A

A - Abbreviation for amp(s)

AC - Abbreviation for alternating currents

ACB - Abbreviation for air circuit breaker

air circuit breaker (ACB) - Large circuit breaker typically used for high current, industrial applications

alternating current (AC) - A current that alternately flows in each of two direction. The time between current reversals is usually constant, producing a constant frequency. The waveform of current plotted against time is assumed to be symmetrical around zero, giving a sine wave. The term is normally only used to refer to the mains power supply.

Amps, ampere (A) - Unit of measure of electric current

Analogue signal - A signal which represents the size of another quantity, such as temperature or pressure, through the size of its own signal level.

ANSI - Abbreviation for American National Standards Institute. ANSI C2.41 is now designated IEEE C6241. See references.

AS - Abbreviation for Australian Standard

Asymmetrical - See common mode

Armouring - Protective metal covering, commonly incorporated on cables and often also used as an earth conductor on power cables

Arrester - Protection device, as in "Lightning Arrester". The term arrester is most commonly used to describe basic protectors for high-voltage overhead power lines.

B

bandwidth - The band or range of frequencies which can be occupied by a signal. Signals outside the nominated bandwidth of a system may be distorted, loosing, or corrupting information

blackout - A total break in the supply lasting from several milliseconds to many hours. Also referred to as an outage or power cut.

bond - To connect metal parts of a system together so that they are at a common voltage, usually earth potential.

brownout - Sustained reductions in the supply voltage, lasting more than a few seconds. Also referred to as undervoltage.

BS - Abbreviation for British Standard