Glossary of Terms

Horace He

Last Updated: December 28, 2022

Glossary of Terms


Alternating Current (AC)

Electric current that continually reverses its direction. The frequency is measured in cycles per second called Hertz. AC is the primary type of power source in residential and commercial applications.  There are two AC frequencies: 60 Hertz in the US (countries that follow American standards) and 50 Hertz in Europe and countries following European standards.

Ambient Lighting

The light within a given area. Light sensors work by detecting the ambient Illuminance to automatically turn the light on/off. Usually, the ambient light value is set to 15Lux, 25 Lux and 35 Lux by default.

Ampere / AMP

The unit of current. One ampere is the current flowing through one ohm of resistance at one volt potential.



Ballast is an electrical device used in a fluorescent lighting system that regulates and furnishes sufficient current, and voltage to lamps and lighting fixtures. 


A light bulb is a self-contained light source, that screws into a light socket in a light fixture. Typically a glass or plastic dome covers the light source itself (filament or LEDs). This is different than a fixture, the bulb screws into the fixture.



Compact Fluorescent Lamp (CFL)

A compact fluorescent lamp (CFL), also called compact fluorescent light, energy-saving light and compact fluorescent tube, is a high efficiency fluorescent lamp designed to replace an incandescent light bulb. The lamps use a tube which is curved or folded to fit into the space of an incandescent bulb, and a compact electronic ballast in the base of the lamp.

The shape of compact fluorescent lamp is very typical


The rate of flow of electricity in a circuit, measured in amperes.


Daylight harvesting

Lights are dimmed up or down in respond to ambient levels of daylight to maintain a set light level as specified by the designer to meet the relevant standards required. Daylight harvesting is also known as ‘Maintained illuminance’ and ‘Daylight monitoring’.

Direct Current (DC)

An electric current which flows in one direction only.


An electronic device or system connected to a light fixture to adjust the intensity of light output. Dimmers can lower the brightness of light to save energy and provides longer lamp life for incandescent, halogen, or low voltage sources.

Dual-technology Motion Sensor

Dual-technology motion sensors use two methods to detect motions. In most cases, they use a combination of PIR and ultrasonic technology to provide better motion detection performances. 


Fluorescent Lamp

A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. 

Fluorescent Lamp



A conducting connection between an electrical circuit and the earth or other large conductions body to serve as an earth thus makes a complete electrical circuit.

Ground Wire

A ground wire is an electrical wire that extends into the ground to give excess electrical charges a safe place to go for higher security purposes.


Halogen Lamp

A type of incandescent lamp with a small amount of a halogen added to the tungsten filament. The combination of the halogen gas and the tungsten filament redeposits evaporated tungsten on the filament, increasing its life and maintaining the clarity of the envelope.


Heating, Ventilation & Air Conditioning.



International Electrotechnical Commission, is an international standards organization that publishes international standards for all electrical, electronic and related technologies.


The “lighting level” measured in foot-candles, which indicates the density of light on a surface per unit area, i.e. how much light is falling on a given area (ft-C = lm/ft2 or lux = lm/m2).

Incandescent Lamp

An electric light with a wire filament that glows and gives off light when heated by an electric current. They are low costs and work equally well on either AC and DC.

IR (infrared)

Electromagnetic waves in the frequency range just below visible light corresponding to radiated heat. IR waves are often used for detecting motions in motion sensors. 


Lamp life

Average time of the lamp that is capable of producing light before it fails. Usually, it’s defined as the point in time when 50% of the lamps have burned out.

LED (Light-Emitting Diode)

A semiconductor light source that emits light when current flows through it.  They are 90% more efficient than incandescent light bulbs, extremely long life and produce little heat on object being illuminated.

LED lights are widely used everywhere

Line Voltage

The standard 120 V power provided by receptacles and for lighting fixtures in commercial spaces in the United States and Canada.


A luminaire or light fixture is an electrical device containing an electric lamp that provides illumination. All light fixtures have a fixture body and one or more lamps. The lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place.


Motion Detector / Motion Sensor

A motion detector or motion sensor is an electrical device that utilizes a sensor to detect nearby motion, particularly people. Typically, in the lighting control sector, there is PIR technology motion sensor, ultrasonic technology motion sensor and dual technology motion sensor that use a combination technology of both. Motion detectors are also known as ‘presence detectors’.


Occupancy Sensor

An occupancy sensor is an indoor motion sensor used to detect the presence of a person to automatically control lights or temperature or ventilation systems. The purpose of using occupancy sensor is to save energy and increase convenience by automatically turning lights on when space is occupied and off when space is vacant.

An ceiling occupancy motion sensor


Passive Infrared Sensor / PIR Sensor

A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors.


A control agent for fixtures that can automate light levels. Some photocells qualify controls for certain rebates and incentives.



If a switch is activated and no movement is detected the lights will switch off after a pre-set time.


UL Listed

A product that has been tested and listed by UL.


Vacancy Sensor

A device that detects the absence of people in a space and provides automatic switching or dimming of lighting.  The primary purpose is to automatically turn lighting Off when an area is not occupied to ensure energy savings. A vacancy sensor relies on a person operating a manual switch to turn lighting On (Manual On/Auto Off).


The electrical power, in volts, of force/pressure supplied by an electrical circuit to a lighting source. Standard US power supply is 120 V 60 cycle (277 V 60 cycles in commercial spaces). Standard power internationally is 220/240 V 50 cycles. It is conceptually the “pressure” of the power supply similar to the psi pressure in a pipe.


Wall Box

A metal or plastic enclosure housing one or more electrical devices.  USA standard 1 gang size is 2” wide x 3.0” high.  The UK standard 1 gang wall box size is 86mm (W) x 86mm (H) (3.425” x 3.425”).  Also known as switch box or back box.

A US standard single gang wall box
A 86 Type, UK and European standard wall box

Leave a Comment

Your email address will not be published. Required fields are marked *

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.