The Basics about LED Lighting

An LED (Light Emitting Diode) is a special diode that uses a semiconductor chip to produce light when an electric current is passed though it. LED lights are extremely energy efficient and long lasting making them ideal replacements for traditional power hungry halogen and standard incandescent lights and can save up to 90% on household lighting costs. The following terms will introduce the LED light to you. Do not hesitate to contact Henkoly if you have any more questions about this wonderful, little invention!

What is LED?

An LED is a semiconductor electronic component that emits light. LED is an abbreviation for Light Emitting Diode.

LED Lights contain no mercury or other toxins and emitt no harmful UV rays and less CO2 than standard incandenscent bulbs. LED’s are a practical replacement for halogen or standard lights as they have a lower energy consumption, longer lifetime, improved brightness, smaller size, faster switching, and greater durability and reliability.

Until recently LED’s have only been used for display type indicators in electrical devices such as TV’s, calculators and clocks or as decorative lighting, as high brightness could not be achieved. Advancements in technology in recent years have opened up LED’s to be used in a wide range of applications in commercial, industrial and domestic lighting.

LED Myths

Myth #1: LED Lights last forever

Fact: LED Lights have an extremely long lamp life in comparison to incandescent and fluorescent lights but they will slowly fade over time.

Lumen depreciation is accelerated by using LED Lights with incompatible drivers or by over heating the LED. This can cause the LED Lights lamp life to decrease from 80,000+ hours to 10,000 hours. When LED Lights are used with the correct driver, LED Lights can achieve 80,000+ hours of life while maintaining 70% of the original light output. LED lamp life can be extended with the use of proper thermal control via heat sinks or by using LED Lights in conjunction with a LED specific Dimming Driver.

Myth #2: LED Lights are not bright enough and have poor light quality

Fact: LED Lights are bright enough to be seen even in daylight and have colour temperatures ranging from 2,500K to 6,500K with Colour Rendering Index (CRI) numbers of 75+.

LED Lights are now used in most traffic lights, which is certainly a sign that LED Lights are bright enough to be seen even in daylight. LED Lights have enough light output for use in very large outdoor daylight visible installations and can sufficiently light entire rooms, tunnels and buildings. Colour temperature describes the apparent visual warmth or coolness of a light source. LED Lights are available in colour temperatures ranging from Warm White (2,500K) to Daylight (6,500K) making them suitable for any application. Colour Rendering Index (CRI) is a metric used to measure the quality of light out of 100. LED Lights have a CRI of typically between 75-85 but some high quality LED Lights can have a CRI of 90+.

Myth #3: LED Lights hardly use any power

Fact: LED Lights use only 15% of the energy a standard halogen uses and provides up to 85% of the light output.

A standard 50W halogen lamp turns 90% of electricity used into heat with only 10% into light. LED Lights use only 15% of the energy a standard halogen uses and provides up to 85% of the light output, making them very energy efficient.

Myth #4: LED Lights don’t give off any heat

Fact: LED Lights do not give off any radiant heat, but they do need to get rid of conductive heat in order to achieve long life.

LED Lights are cool to touch and give off no radiant heat in the direction the light is being dispersed. Behind the LED Light, in the circuit board or heat sink, the energy that is being turned into heat is being dispersed. LED Lights need proper thermal design, which is why some can come with heat sinks. The heat emitted by LED Lights is 90% less than the heat emitted by halogen lights. With the advancement in technology, LED Lights will become increasingly efficient by enabling more light output per unit of energy, which will emit less heat and reduce the need for heat sinks.

Myth #5: LED Lights are really cheap

Fact: LED Lights are more expensive than incandescent and fluorescent lights but are getting cheaper at an impressive rate and have a payback period of less than two years.

The cost of LED Lights, as measured by dollars per lumen, has reduced by 50% in the past year. While it still makes LED Lights currently more expensive to buy than incandescent and fluorescent lights, it is expected that there will be a further 80% price reduction in LED Lights over the next four years. The payback period for replacing incandescent and fluorescent lighting with LED Lights is under two years as LED Lights last  up to 10 times longer than halogen lights. An LED Light lasting for 50,000 hours would last for an incredible 24 years if used for 6 hours per day for 365 days in a year.

History of LEDs

In 1907, British scientist Henry J. Round dicovered the physical effect of electroluminescence, an optical and electrical phenomenon in which a material emits light in response to an electric current passed through it or to a strong electric field. The light produced was very dim and not bright enough to stimulate further research.
In 1962 the first visible spectrum  LED light was produced by Nick Holonyak Jr. and was red in colour. This coined his nickname, ‘Father of the Light Emitting Diode’. The red LED’s were not bright enough to be seen in daylight so the first LED applications were mainly used as indicator lights for military use.

M. George Craford, a student of Holonyak, invented the first yellow LED in 1972 and then went on to produce a much brighter red LED.

As technology progressed in the 1970’s additional colors were created and as new colors became available, new uses for LED lights were in demand. LED’s were used in applications such as calculators, digital watches and test devices.

The first superbright LED’s were developed in the 1980’s and were brighter, more stable and cost efficent which saw the demand for LED’s rise dramatically.

From 1990 the use of LED’s became standard in various industrial applications from switch cabinets to measuring instruments, in consumer products such as Hi-Fi equipment, telephones or personal computers and in traffic signal installations for road and railway or in indoor and outdoor automotive lighting.

For  two decades LED lights have been replacing incandescent globes in homes and businesses, offering a cheaper, more efficient service in a wide variety of contexts.

Benefits of LED Lighting

The benefits of LED Lighting are endless. LED Lights are energy efficient, cost effective, durable and more. They are the lastest technology in lighting and offer a great alternative in replacing your current halogen or standard lights. Below is a detailed list of some of the many benefits of LED Lighting.

Energy Efficient
A standard 50W halogen lamp turns 90% of electricity used into heat with only 10% into light. The benefit of LED Lights are that they use only 15% of the energy a standard halogen uses, provide up to 85% of the light output and create less heat making them so cool to touch. This makes LED Lights not only energy efficient but extremely cost effective as air conditioning use can be lowered. Some LED Lights can be operated by mains power, but when used with a Low Voltage LED Driver, LED Lights will produce more light output per watt.

Long Life Span
LED Lights have the benefit of a super long life span of up to 80,000 hours which means you can cut maintainance costs as the lamps last up to 8-10 times longer than standard halogen lamps making them an ideal replacement.

Improved Durability
LED’s have no filaments so can withstand a greater intensity of vibration and shock than stardard lights making them durable with less risk of breaking and need to replace.

Compact Size
LED Light bulbs can be as small as 2mm making them ideal for fitting into hard to reach and compact areas.

Fast Switching
LED Lights will start at full brightness, instantly, every time, therefore there is no need for backup lighting. LED Lights are a benefit because they switch on and off instantly making them ideal for flashing signs, traffic signaling and automotive lights, compared to standard compact fluroescent lights which fade in and out or flicker.

Most LED lights operate at low voltage so are cool to touch and much safer to handle during installation and maintenance and can be exposed to rain and snow.

Environmentally Friendly
The benefit of LED Lights is that they are an eco-friendly form of lighting as they do not contain mercury or other harmful gasses or emit any harmful UV rays. For example, a 13w LED light emits 68% less CO2 than a standard 40w incandescent bulb running 10 hours per day.

Lighting Terms

Accent Lighting:

Directional light that is used to emphasise or highlight a particular object.

The standard unit of measurement for electric current that is equal to one coulomb*, per second. It defines the quantity of electrons moving past a given point in a circuit during a specific period.

Abbreviation – Amp

* Coulomb – A unit of electrical charge, is defined as the amount of electric charge transported by a current of 1 ampere in 1 second.

A device which is used to supply sufficient voltage to start and operate Fluorescent and HID lamps, while limiting and regulating the lamps current during operation.

Bayonet Cap Base:
A type of lamp base with a pin on either side which locks the lamp into place when placed in the lamp socket.

Beam Angle:
The degree of width that light emanates from a light source.

An outdoor light fitting that which is a very sturdy vertical post with the light source located at or near the top. Bollards are typically used to light up walkways in commercial areas.

Brick Lights:
A light fitting that can be recessed in a brick wall, in order to light up a walkway, step a landing or a pathway.

Another term for a lamp.

An electrode that emits electrons*. A fluorescent lamp cathode emits or discharges electrons to the cathode at the other end of the lamp.

* Electrons – An electron is a negatively charged component of an atom.

Colour Rendering Index:
Colour Rendering Index also known as CRI, is a measure of the ability of a light source to reproduce the colour of various objects faithfully in comparison with an ideal or natural light source. The CRI simply rates the colour rendering out of 100, the higher the index the better the colour rendering.

Colour Temperature:
Colour temperature is a measure of how warm or cool the light given off by a lamp appears. ‘Warm’ colours appear tinged with yellow and generally feel soft and cosy. Cool colours are tinged with blue and appear whiter, making them a more ‘honest’ and unforgiving light more suitable for working environments than relaxing. The way to measure light is through the Kelvin Temperature scale.

Compact Fluorescent Lamp:
Compact Fluorescent lamp also known as CFL are often used as an alternative to incandescent lighting. They have a high colour rendering and a lamp life of about 5 times longer than incandescent lamps.

Cove Lighting:
Cove lighting is a form of indirect lighting built into ledges, recesses, or valences in a ceiling or high on the walls of a room.

A translucent piece of glass or plastic sheet which shields the light source in a fixture. The light transmitted throughout the diffuser will be redirected and scattered.

A device in an electrical circuit used for varying the brightness of lamp in a lighting installation.

Direct Current:
A Direct Current also know as DC, is an electric current that has no alterations.

A light fixture which is usually completely recessed into the ceiling that concentrates most of the light in a downward direction. It may feature an open reflector and/or a shielding device.

Edison Screw Base:
A lamp base that screws into it’s matching socket when rotated clock wise.

A metric used to compare light output to energy consumption. Efficacy is measured in lumens per watt.

Electronic Ballast:
A ballast that uses semiconductor components to increase the frequency of fluorescent lamp operation.

Emergency Lighting:
Lighting used when the normal lights fail, such as exit lights.

Variation in light intensity due to 50 Hz operation. Can cause eye strain and fatigue due to stroboscopic effects.

A broad-beamed, high intensity, artificial light source generally used for industrial and commercial applications.

Fluorescent Lamp:
A light source consisting of a tube filled with argon, along with krypton or other inert gas. A phosphor coating on the inside of the glass tubing transforms some of the ultraviolet energy created inside the lamp into visible light when electrical current is applied.

The English unit of measurement of the illuminance (or light level) on a surface. One footcandle is equal to one lumen per square foot.

The number of times per second that an alternating current system reverses from positive to negative and back to positive, expressed in cycles per second or hertz (Hz).

Direct glare is caused by light coming directly to the eye from a light source. Indirect glare is light reflected from a surface in the direction of the eye. Both can harm vision and cause visual discomfort, annoyance or loss of visual performance.

GU10 Lamp:
These lamps have a turn-and-lock base, so they cannot be accidentally interchanged with low-voltage lamps. Their filaments are finer and they are much more fragile than those used in low-voltage lamps and have a far less lumen output than the low voltage lamps. LED lamps have been developed as GU10 to be operated directly on mains voltage, but unlike Halogen types, they perform the same as low voltage lamps. They can house electronic drivers direct off the mains power and can perform more efficiently and can also be made dimmable using standard residential phase cut dimmers

Halogen Lamp:
A type of incandescent lamp that contains halogen gases, which slow down the evaporation of the tungsten filament.

Lighting used in Industrial applications where the ceiling height is greater than 20 feet.

High Intensity Discharge Lamp:
High Intensity Discharge lamp, also known as HID, is a generic group of lamps consisting of mercury, metal halide and high pressure sodium lamps.

The amount of light arriving at a surface, expressed in lumens per unit area; 1 lumen per square foot equals 1 footcandle, while 1 lumen per square metre equals 1 lux.

Ingress Protection Ratings:
Ingress Protection ratings, also known as IP ratings, are used to specify protection from the environment.

First IP Number – Protection against Solid Objects

0 No special protection
1 Protected against solid objects up to 50mm, eg. Accidental touch by person hands.
2 Protected against objects up to 12mm, eg. Persons fingers
3 Protected against solid objects over 2.5mm (tools and wires).
4 Protected against solid object over 1mm (tools, wires and small wires).
5 Protected against dust limited ingress (no harmful deposit.
6 Totally protected against dust

Second IP Number – Protection against Liquid

0 No protection.
1 Protected against vertically falling drops of water.
2 Protection against direct sprays of water up to 15° from the vertical.
3 Protected against direct sprays of water up to 60° from the vertical.
4 Protected against water sprayed from all directions – limited ingress permitted.
5 Protected against low pressure jets of water from all directions – limited ingress permitted.
6 Protected against temporary flooding of water, eg. For use on ship decks – limited ingress permitted
7 Protected against the effect of immersion between 15cm and 100cm.
8 Protected against long periods of immersion under pressure.

Kelvin Temperature scale:
The way we measure light is through the Kelvin Temperature scale. This standardised colour scale is created by heating a theoretical black body, starting out at zero degrees Kelvin (Absolute zero) as the body heats up, it glows, like any other object would. As the heat increases the colour changes, appearing first dark red then yellow, moving through the visible colours of the spectrum until it reaches blue and violet.


Light Emitting Diode:
Light Emitting Diode, also known as LED, a small electronic device that lights up when electricity is passed through it. LED’s have a very long life and come in a variety of colours, the most common are Warm White, Cool White, Red, Green and Blue.

Low voltage lighting systems usually operate on 12 volts and 24 volts. Low voltage lighting systems uses a transformer (electronic or magnetic) to transform the “incoming” voltage (usually 240 volts) to 12 or 24 volts.

A unit of light flow. The lumen rating of a lamp is a measure of the total light output of the lamp

Light Output LEDs CFLs Incandescents
Lumens Wattage Wattage Wattage
450 4 – 5 8 – 12 40
300 – 900 6 – 8 13 – 18 60
1100 – 1300 9 – 13 18 – 22 75 – 100
1600 – 1800 16 – 20 23 – 30 100
2600 – 2800 25 – 28 30 – 55 150


* Please note that these lumen values are approximate, they may vary due to different manufacturers.

The metric unit of measurement for illuminance of a surface. One lux is equal to one lumen per square metre.

Mercury Vapour Lamp:
A type of hight intensity discharge (HID) lamp that uses mercury in an excited state to produce light, most of which is produced by radiation from mercury vapour.

Metal Halide Lamp:
A HID lamp that produces light by radiation from certain metallic vapours when supplied with electricity from a ballast.

MR16 Lamp:
MR16 lamps contain single-ended quartz halogen filament capsules with a multifaceted reflector (MR); a pressed glass reflector with the inside surface composed of facets and covered by a reflective coating. These facets provide optical control by gathering the light from the filament to create a concentrated beam of light. The reflective coating can be either Dichroic or Aluminium. Most MR16 lamps are operated using voltages lower then 120 volts, typically 12V.  MR16 lamps can be dimmed through commercially available dimmers for low voltage loads.

Pendant Lighting:
Pendant Lights can provide both task and general lighting, equipped with shades or globes to avoid glare. They are suspended from the ceiling over dinette tables, kitchen counters or other work areas.

The rate at which energy is taken from an electrical system or dissipated by a load, expressed in watts (W); power that is generated by a utility is typically expressed in volt-amperes (V-A).

A device used to redirect the light by the process of reflection.

A device used with a ballast to start and preheat fluorescent lamps.

An electrical device that transforms the line voltage of a facility into the voltage that a low voltage lighting system requires.

Vandal Resistant:
Fixtures with rugged housing, break resistant type shielding and tamper-proof screws.

A volt is the potential difference that will cause 1 ampere to flow through one ohm resistance.

The standard metric unit of measurement for electrical potential. It defines the force or pressure of electricity.

Watt is the unit for measuring electrical power. It defines the rate of energy consumption by an electrical device when it’s in operation. It is defined by the current voltage. The energy cost of operating an electrical device is calculated as its wattage times by the hours of use.

There you have it, everything that you ever wanted to know about LED lighting and how exactly they are capable of saving you money, by saving electricity, and the planet! If you are curious about all the lighting solutions that we have on offer at Henkoly, feel free to browse through our online LED lighting catalog. Remember as a proudly South African company we can easily provide you with the best LED lighting solutions in your area.