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Electrical Glossary Of Terms

I’m often asked about the meanings of  some of the acronyms and terms we bandy about.  We fall into the same trap that many people do when talking about their work:  we assume that everyone understands what on earth we are banging on about!  So I thought I’d share the meanings of some of the common electrical terms here in an Electrical Glossary: so you have a better understanding of “sparky talk”.

AC  –  alternating current – the flow of electric charge switches back and forth 60 times each second.  AC is the form in which electric power is delivered to businesses and residences.

Ammeter – an instrument for measuring electric current in amperes.

Ampere (amp)  –  standard unit of current. One ampere of current is produced by one coulomb of charge passing a point in one second.

Bandwidth –  the range of frequencies that can be used for transmitting information on a channel. It indicates the transmission – carrying capacity of a channel. Thus, the larger the bandwidth, the greater the amount of information that can pass through the circuit. Measured in Hertz MHz km (for fibre) or MHz.

Circuit Breaker – an electrical protection device that automatically switches to off when overloaded.  Same as RCD.

Coulomb (C) – a quantity of electricity transferred by a current of one ampere in one second.

Conductor – an electrical conductor is any thing or any material which can carry an electric current – eg: copper wire.

DC – Direct current.  The type of electricity stored in batteries and generated by solar electric devices. Current flows in a single direction.

Fibre optic – A fibre optic cable in which individual optical fibres are formed into a cable.

Fuse – a short piece of wire, that will conduct current continuously up to a certain level, but melt if the current rises significantly above that level. It ís also designed to become an open circuit when it does blow – automatically switching off the current before any serious damage is done.

Halogen Lamp – a light where the filament is contained in a bulb that is filled with a gas mixture that includes a gas from the halogen ‘family’, for instance iodine or fluorine. A halogen light has a longer life than a normal filament light and does not lose brightness over its lifetime.

Hertz (Hz) – The frequency, or number of times per second, that the flow of AC electricity reverses itself.

Incandescent Lamp – filament wire lamp.

Isolate – cut off electrically.

Kilowatt (kW) – One thousand watts of electricity. Ten 100-watt light bulbs use one kW of electrical power.

LCD – Liquid Crystal Display is an energy efficient flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals.  LCDs are used in computer monitors, televisions, instrument panels, aircraft cockpit displays, signage, video players, gaming devices, clocks, watches, calculators, and telephones.

LED – light-emitting diodide.  LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved physical robustness, smaller size, lower heat and faster switching. Used in aviation lighting, automotive headlamps, advertising, general lighting, traffic signals and camera flashes.

Laser  – a device that amplifies light waves and concentrates them in a narrow, very intense beam.

Live – anything carrying an electrical current.

Loads – any device that consumes electricity to operate. Appliances, tools, and lights are examples of electrical loads.

Low Voltage (LV) – this includes electrically operated circuits, apparatus, components in which the electrical voltage exceeds extra low voltage ( 120V DC, 50V AC) and is at or below 1000 Volts a.c. or 1500 Volts d.c.

Ohm – the SI unit of electrical resistance, transmitting a current of one ampere when subjected to a potential difference of one volt.

Optical Fibre –  a transmission medium consisting of a core of glass or plastic surrounded by a cladding. Signals are transmitted as light pulses, introduced into the fibre by a light transmitter i.e. Laser or an LED.

Photovoltaic – electricity produced from the sunlight.  An array of Photovoltaic panels provide solar energy to a building or piece of equipment.

RCD – Residual current device or Circuit Breaker – RCDs detect an imbalance in the electrical current and disconnect the power within 10 to 50 milliseconds, preventing electrocution and fire.

Splice – the physical joining of two or more copper wire or optical fibres.

Surge – a sudden voltage rise and fall in an electrical circuit.  Surge protection devices protect equipment from sudden surges and lightning strikes.

Volt (v) – the standard unit of electromotive force or electrical pressure. One volt is the amount of pressure that will cause one ampere of current to flow through one ohm of resistance.

Watt (W) – a unit of measure of the amount of electrical power consumed by a load or supplied by a source.


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