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LED lighting is often written about in a very technical way. Luckily, the people at Digilight are fluent in gobbledygook, so we’ve translated the scientific jargon associated with LED lighting into plain Australian. When broken down, it’s actually not too hard to get your head around. And it helps consumers get a better understanding of how LED lighting compares to older types of lighting.
We have specific pages that give more detailed analyses of the following terms.
For a detailed analysis of LED Colour Click Here
For a detailed analysis of LED Brightness Click Here
For a detailed analysis of LED Distribution Click Here


When we talk of ‘ambient light’ we are referring to the light that surrounds an area. That might be light given off by the sun, the moon or light fittings operating in the same space. Ambient temperatures refer to the level of heat an LED light source is expected to function in. LED lights are tough enough to work effectively in any temperature. Fluorescent lights on the other hand are known for their poor performance in cold temperatures.


Amperage is how we measure electrical current, and electrical current is the flow of electric charge. We can’t see electrical charge, but if we think of it like water flowing through a hose, Amperes are like the rate of that flow. The higher the number of amperes, or amps, the more capacity it has for power and so the more devices that can be placed onto that circuit.
Current (Amps) = Power (Watts) / Voltage (Volts)


The shortened unit of measurement for electrical current is an amp. One volt through a resistance of one ohm produces the flow of one amp.


A ballast is commonly used in fluorescent lighting, and is a device used to control the amount of power getting to the light fixture. It limits the electrical current, acting as a mediator between the high voltage source and the lamp itself, preventing an instant overheat. When the lamp starts up, the ballast does deliver high power to instigate the connection between the voltage source and the lamp, but once that has been set in place, it swiftly decreases the voltage to a safe point. LED lighting doesn’t need a ballast to regulate the electrical current.


An LED is not actually a lightbulb, but rather a bulb that holds LEDs. A bulb is either a light bulb, flashlight bulb, and have different mountings. Common ones are MR16 for 12 V, BC22 (baynet) or Edison Screw (E27). LED lights operate at low voltage, so the bulb has the drivers inside the base of the bulb. An LED light bulb is one such bulb with LEDs installed with electrical components ready for consumption. An LED light bulb is screwed into position, turned and sealed in place and pushed into sockets or contact terminals.

Bulb Base

This is the part of the bulb that’s used to lock it in place and make it connect with electricity. Type and size can vary. The most common would be E26/27, or medium base as it often is called. 26 or 27’s are akin to the measurements of the threads of a screw-in bulb base. This kind of bulb also takes in the PAR 20, PAR 30 and PAR38, as well as a couple of others. There’s also MR16, MR11 and GU10 base LED bulbs.

Candela (cd)

A unit of measuring the strength of brightness, going out in a particular direction. It stems from the pre-technological beginnings of lighting, using the strength of one candle to assess the strength of other surrounding sources of light.

Colour Definition

There are three terms used when describing the colour of evenly lit objects.
* Hue – a situation in which different colours appear similar, such as in matching blues and pinks.
* Lightness – Describes the level of grey between monochromatic colour.
* Chroma – Describes the variation in lightness of the same colour e.g. green, greener, pure green.

Colour Spectrum

The colour spectrum refers to wavelengths of light, which are measured in nanometres. Visible light is recognised as having a wavelength in the realm of 400-800 nanometres. The human eye cannot see light outside of the visible spectrum. ‘You’re not on my wavelength’ is like saying someone is literally incapable from seeing your point of view. Violet is on the shortest end of the spectrum and red is at the longest end. White is a combination of all colours on the spectrum, while black is the complete absence of them. Sunlight consists of the entire spectrum.(nm).

Colour Temperature

Colour temperature describes the effect of heat on an object. The glow, the released radiation and visible colour all change in accordance with temperature. We can imagine it clearly when we think of hot metal rod. It glows red at first, then orange, and ultimately becomes ‘white hot’ as the temperature intensifies. See the FAQ page for more details about colour, temperature for LED lights.

Cool White

A description of light with an associated colour temperature of between 5000K -7500K, typically apparent as a faint blue.

Correlated Colour Temperature (CCT)

CCT is the measure used to understand the colour of a white light source relative to other colours on the spectrum. So CCT will describe available shades of “white” as they relate to warm/cool colours that we can easily envision. For example, LED lighting might be available in a yellow/gold/blue light. CCT IS described in kelvins (the unit of complete temperature.)

Colour Rendering Index (CRI)

CRI is a scale of 1-100 that tells us how natural a colour appears to us. The higher the CRI, the closer the object is to that which appears in nature. So, for example, natural outdoor light had a CRI of 100. LED lighting sources typically range from 60-90, giving a similar light output to natural daylight. This means sharper, naturally coloured images with reduced glare.

Colour Temperature

This is how we measure, in kelvins, the colour of the light source compared with complete darkness at a certain temperature. Incandescent lighting has a low colour temperature, about 2800Kelvins. Daylight comes in at about 6000 K so you can imagine the difference. They don’t call it ‘the harsh light of day’ for nothing. Incandescent lights give off a red-yellowish character. Fluorescent lights are closer to natural daylight, with the most popular coming in at around 4100 K. They tend to appear bluish-white in colour. Lamps with colour temperatures below 5000K will likely take on a yellow-red tone.

Compact Fluorescent Lamp (CFL)

A CFL, or compact fluorescent light is a fluorescent bulb that’s been packed down and altered to the size and fit of a regular incandescent light bulb. CFLs were intended to substitute incandescent lights, fitting into the majority of pre-existing lighting fixtures originally designed for incandescents. CFLs are reputed to last roughly 6x that of incandescent lights and use less power. However, LED lighting has now usurped CFLs as the most energy and cost efficient form of lighting available.


Centre of the LED


An visual component used to blend light rays so that light is distributed evenly.


Like a ballast used for fluorescent lights, an LED driver is a self-contained electrical device used to control how much power reaches the LED light. See also Magnetic Driver

Efficiency versus Efficacy

The efficiency of a light is a ratio of the total amount of energy put in to a lighting fixture to the amount of energy that actually gets used up. For instance, if you take a 100W incandescent light bulb that produces 1,000 lumens, and put it into a lamp that puts out 700 lumens, the efficiency rating 70%. To calculate the efficiency percentage, you divide the used output by the total energy input.
Efficacy concerns itself with the amount of light produced by a certain amount of electricity. This is spoken about in terms of efficiacy, which is spoken about in lumens per watt.
Lumens=amount of light
Watt=amount of power used to create it.


The fixture is the finished product, essentially. It is a complete lighting unit comprising of a lamp or a number of lamps together, with sections intended to dispense light, position and shelter the lamps, and ultimately connect them to the supply of power.

Full Spectrum

Full spectrum refers to light bulbs or lamps that produce a spectrum of light that encompasses the full range of light visible to the human eye (400-700nm) without holes in its spectral output. White LEDs are characteristically a full spectrum source of light as they are the closest to natural daylight.

General Illumination

General illumination distinguishes between lighting that puts a spotlight on tasks, spaces, or objects as opposed to lighting that is used purely to indicate something or only serves a decorative purpose. It is commonly provided by white light sources like incandescent, fluorescent, HID’s and white LEDs. Indication or decorative lighting is typically monochromatic, such as in exit signs, brake lights, traffic lights, and signage.

HID versus LEDs Lighting

Ultra-bright white LEDs have the benefit of minimal lumen depreciation. This just means that the light they give out fades gradually rather burning out instantly like HIDs. In fact, after 100,000 hours, LED lights will still produce 70% of their light output. That’s over 11 years of non-stop lighting with only a 30% total decrease. LEDs also have superior optical efficiency and a higher number of lumens per watt. What this means is that the light they give out is more evenly distributed, the light is sharper, crisper and reflects colours as they would naturally appear in daylight. When we say that it has a higher number of lumens per watt, we mean that more of the energy being used to create light is actually being used for that purpose, rather than HID lights, where as much as 70% of the energy generated is used to produce wasted heat. LEDs last significantly longer than older light sources. Traditional incandescent light bulbs only have a life expectancy of 1,000 hours. LED lighting offers at least 50x that.

HID vs LED Life Cycle Comparison

People often question how LED lighting can deliver lumens more efficiently than their HID counterpart s when their initial lumen output is actually lower than HID lights. The answer is in the average amount of lumens delivered over a 60,000 hour life cycle. LED lighting outperforms a HID light by 74%. It is also worth taking into consideration that a 60,000 hour life cycle involves 3 relamps in the case of HID lights. LED lighting requires little to no maintenance and has and has a more efficient energy supply so doesn’t need re-lamping at all.


This is a measure of how much light is striking a specific area. Bulbs on their own are measured in lumens while lighting fixtures are measured in lux (lumens/sq.meter).

Kelvin Colour Temperature

This is a measurement of the light’s colour relative to darkness at a temperature given in degrees Kelvin (K). Incandescent lights have a colour temperature of around 2800K which is relatively low. They take on a red-yellowish tone. Natural daylight is the highest on the scale with a colour temperature of 6000K. It appears bluish in tone, which is the most sought after colour in fluorescent lighting, with a rating of 4100K. The compounds used in fluorescent lamps that give light when energised can be mixed to produce any colour temperature in the range of 2800K- 6000K. A colour temperature under 5000K will likely be a yellow/red hue. Lights with a rating between 5000-6000 are seen as white and lamps above 6000K typically have a blue tint.

Junction Temperature

This is the temperature point where one diode connects to its base. Keeping a low junction temperature increases output and slows the rate at which LED lighting fades. Junction temperature is crucial to assessing the quality of an LED product as well as its capacity to last.
3 things affect junction temperature. These are:
* drive current
* thermal path
* ambient temperature
Generally speaking, the more powerful the power supply aka the drive, the more heat that is produced at the die. Heat needs to be moved away from the die to preserve life-span, light output and colour of the LED product. To get the most from LED’s, the junction temperature should be kept as low as possible and keep within manufacturer specifications.

LED (long definition)

A Light Emitting Diode (LED) An LED is like a tiny light bulb that turns electrical energy into light. They are illuminated by the movement of electron in the semiconductor, which is made up of 2 sections. The electrons move between the two sections when we apply voltage. This process releases energy, and as that energy spreads, photons-tiny particles of light-are created. LED technology has been used for decades as indicator lights for various electronic devices, including alarm clocks, remote controls and microwaves. In recent years, LED technology has evolved into a sustainable option for domestic and commercial lighting.
Check out this website for more info on LEDs.

LED (short definition)

LEDs are light emitting diodes. Unlike incandescent lights, they don’t need a filament to heat up in order for them to light up. This means that they never reach extremely high temperatures and never burn out. A LED isa solid slate device where electricity passes through a chemical compound that produces light when excited.

LED Ambient temperature vs efficiency

LED lighting fixtures have to be designed with junction temperature thermal management. Thre is kept as low as possible so the efficiency rating can high and the longevity of the LED fixture remains intact. It’s also vital to use the correct LEDs. When manufactured correctly, LED lighting will be strong enough to perform in extreme temperatures. Fluorescent lighting performs poorly in cold temperatures, while LED lighting is unaffected.

LED Life span

LED lights endure significantly longer than incandescent, fluorescent or HID lamp sources. They have a general life-span of 50,000 hours or longer. LED fades gradually, which is known as lumen depreciation. The Illuminating Engineering Society’s (IES) current standard for calculating the life of an LED is the point at which the LED reaches 30% lumen depreciation. So even when an LED has ‘died’ it will still emit 70% of its original lumen output.
It’s important to note that a 100,000-hour life rating does not mean the LED will last 100,000 at full capacity. At 100,000 hours it still be working, but at a decreased lumen output.

Life-100,00 hours- how long

How long is 100,000 hours?
100,000 hours in real terms:
24 hours a day 11.4 years
18 hours per day 14.8 years
12 hours per day 22.8 years
8 hours per day 34.2 years

LEDs - where are they used?

The lighting industry started to using LED in the late 1990’s, mostly using it for aesthetic, effect or speciality lighting such as architectural highlighting. LED lighting has quickly progressed due to its superiority in all performance areas. Now, it is the optimum choice for street lighting, parking structures, commercial, industrial and domestic lighting It has usurped its predecessors in economic sustainability and practical performance. Not only has the quality and performance of LED lighting greatly improved over the years, but it continues to evolve and improve today.

LEDs - are they Green?

LED luminaires are eco-friendly for a number of reasons:
1. They contain zero mercury. Mercury is poisonous, and when not disposed of correctly, can wreak havoc on the environment and threaten plant and wildlife species. Many consumers are unaware of the currect procedure regarding the disposal of incandescent lightbulbs, and so millions are carelessly dropped in landfills every year. Standards (RoHS), compliant,
2. They last longer. A lot longer. This means that as well as saving money on your power bill, you save money and time on replacements.
3. They produce less waste.In terms of weight, almost a quarter of the product is made using recycled materials like aluminium castings and extrusions.
4. Nearly three quarters (by weight) of LED lighting fixtures are readily recyclable.
5. LED circuit boards, drivers, wires and connectors are all non-hazardous, mercury-free, and RoHS compliant.

LED Replacement

LED lights don’t burn out like traditional filament lamps, so it’s not like individual diodes need to be replaced. Instead, the level of light output the diodes produce decreases gradually over a long period of time. If one diode fails, it won’t produce a complete fixture outage. If you think of Christmas lights, it’s common to find one or two aren’t working, but this does not affect the complete set.

LED Advantages

LED lighting has an advantage over its competitors in every respect.
* High efficacy and durability mean that they will last longer than other lamp sources, a lifetime in some cases.
* Low maintenance. Without the need for costly and often inconvenient replacements, consumers save money, save energy and save the planet all at the same time.
* Greater optical control. Dimming, instant on/off, and reduced rate of lumen depreciation mean that consumers can apply the required amount of light to a particular task, or create the desired mood in a room.

LED Degradation

The rate of lumen depreciation depends on the manufacturer, based on their luminaire designs. Thermal design plays a pivotal role in the rate so you will see variation in lumen depreciation from manufacturer to manufacturer, as well as within different product categories offered by the same manufacturer.

Lumen Distribution

The Illumination Engineering Society (IES) classifies varying light distribution patterns into different categories or “types” (i.e. Type II, Type III, etc.), w]Within these classifications, there is more variation again. Two manufacturers may both have products classified as a “Type III” distribution, but the light distribution may vary. It is wrong to assume that any two products with the same IES classification will provide identical or even a similar light distribution pattern. The only way to see that is in the practical application of each product.


Low Bay Lighting is that which is designed for areas where the base of the lighting fixture is less than 20 feet above the floor. Fixtures are usually 22-28″ in diameter in order to distribute uniform light.


Lumens are how we measure in units, the amount of light emitted per second in a given area. Lighting fixtures are measured by lux output which is lumens per square meter.


A complete lighting fixture complete with installed lamps and other accessories.

Luminous Efficacy

Efficacy Is the common measure of a light source’s efficiency. It’s stated in lumens per watt (lm/W), indicating the amount of light produced for each watt of power used.


Lux is a measurement of a light fixture’s brightness, or intensity. The higher the lux reading, the more light that is given out over an area. This is measured in lumens per square meter.


A device that alters the course of a ray of light, either by reflection (e.g. a mirror), or by refraction (e.g. a lens.)

PAR (Parabolic Aluminium Reflector)

Parabolic refers to the curved shape of the base, which works to catch light and dispel heat created by the LED. This unit is screwed or plugged into a casing, known as a can, tract light or some other fixture.

LED Package Design -Does it matter?

More so than previous technologies, definitely. The manufacturer has more influence over the rate at which your LED product will fade. Thermal design, which manages how hot your LED will get, controls that rate. S as thermal design varies from manufacturer to manufacturer, so too will variation in lumen depreciation. The rate of depreciation in different products by the same manufacturer may also vary.


RGB stands for the 3 primary colours- red, green, and blue. The 3 primary colours combined create the colour we know and see as white. It stands to reason that combining red, green, and blue LEDs produces white light. There is another method to creating white light known as phosphor conversion which involves coating blue or near ultraviolet diodes in yellow phosphor.

Solid-State Lighting

Refers to devices that use LEDS, organic LEDs or Light Emitting Polymers to create light. They don’t contain a filament or any moving parts which can cause a light fixture to crack rupture, or leak hazardous substances into the environment.

Task Lighting/Lamp

LED lighting designed to shine a light on a particular area so that you perform tasks such as reading, working or cleaning. It may be a high powered LED in any form but is usually a desk lamp, floor or clamp-on lamp.


The simplest way to understand voltage is as a push. Like water needs to be pushed through a hose to get it to wash your car, electricity needs to be pushed through a circuit to make your light switch go on and emit light. This push is the rate at which the power is being drawn from the supply and it is measured in volts. .


A volt is the unit of measurement for voltage. The more volts there are, the more pressure that can be applied, and more power that can be transmitted, and used.

Warm White

Natural daylight has a colour temperature of around 6000 kelvins. The colour temperature goes down as the colour draws away from natural light into blackness. So at 3000-3500 Kelvins, warm white gives off a slightly yellow hue. LED lighting gives consumers a choice of colour when it comes to lighting. Warm white works to create a softer, more homely ambience in the evenings when it is needed. Conversely, rooms which don’t get a lot of sun might suit a cool white light that has a colour temperature closer to natural daylight.


We use watts to measure electrical power. I t tells us the rate at which an electrical device uses energy when it’s turned on. The power costs involved in operating an electrical appliance is calculated as wattage multiplied by hours of use.

White Light

The white light produced by mixing the 3 primary colours-red, green and blue. White light is expressed in Kelvins, and is the closest to the light given off by the sun which has the highest colour temperature. It corresponds with the colour emitted at the highest degree of heat.


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The New Zealand website is at www.digilight.co.nz