How Do LED lights work?

Recent changes in legislation across Europe, and many other areas of the world, have outlawed traditional light bulbs in favour of LED light bulbs. There is still a lot of misinformation and confusion surrounding LED lighting. Even though LED lighting technology has been around for more than 100 years, it is still something of a mystery to many people. So, how do LED lights work and what does the future hold for them?

Do LED lights produce heat?

Many people don’t realise but heat is actually a by-product of lighting. LED lights produce a fraction of the heat associated with traditional incandescent light bulbs and other sources of lighting. Obviously, different types of LED light will emit different levels of heat but on the whole, the heat created using LED lights is only around 20% of that from incandescent light bulbs. As a consequence, the LED light bulb in your home is cool to touch and you can take your time replacing any diminished LED lights. You won’t burn your hands!

LED lights also use what is known as a heatsink which absorbs and releases what little heat is created. As a consequence, there is no fire risk with LED light bulbs and they will save you a significant amount in electricity costs.

Are LED lights brighter than traditional light bulbs?

To answer this question we need to understand how both incandescent lights and fluorescent lights work. An incandescent light works by passing an electric current through a filament. As the filament is heated, this creates light but also a huge amount of heat. The filament, made of ductile tungsten, is located in a gas-filled tube which when heated gives the glow.

Fluorescent lighting works in a very different way to incandescent bulbs. They basically ionise mercury vapour in a long glass tube. This creates UV light which is then converted into visible light using a phosphorus coating on the inside of the fluorescent tube. When you see a fluorescent light switched on, it can take some time to warm up. Unfortunately the use of mercury within the light brings us on to the dangers of this type of lighting. So, how do LED lights compare to traditional light bulbs?

LED lights work in a very different fashion. They have a two lead semiconductor light source which charges electrons when a voltage is passed through. This allows the electrons to “recombine” within the holes in the LED light device. This then releases energy in the form of photons which creates the light. The brightness of an LED bulb is dictated by the high lumen/watt score which is in effect a measure of the light created. Due to the high efficiency of LED bulbs, a traditional 40 W incandescent bulb would create 450 lm. A 40 Watt LED light bulb would create 3550 lm and will be nearly 8 times brighter despite using the same wattage.

Therefore, you will be able to create the same brightness of a 40 Watt incandescent bulb using a maximum 8 Watt LED bulb. As a consequence, not only are there huge cost savings between the two types of bulb but LED lighting can be much brighter – with just a fraction of the energy used by incandescent lighting.

Do LED lights have a wire filament?

In simple terms, LED bulbs do not have any form of wire filament – which is used in their incandescent bulb counterparts. The light from an LED bulb is created by passing an electric current through a semiconductor which emits light energy. The light created is very direct, very strong and very bright. There is no need for gas-filled bulbs, reflective materials magnify light – LED light bulbs only create 20% of the heat associated with traditional lighting.

The wire filament method has been commonplace for many years but is extremely inefficient. The huge amount of heat created during the lighting process is in effect wasted energy. There is also the brittle nature of the wire filament compared to the more robust semiconductor material used in LED lighting. In general LED lights are much more robust and the days of seeing a broken filament in an incandescent light bulb have gone forever!

What is LED flash?

As LED lighting technology is developed and expanded, we are starting to see the emergence of new and sometimes confusing terminology. LED flash is one such terminology which is confusing some people. The most common use of LED flash is within mobile phones with digital camera or video camera capabilities. This is the light source for your mobile phone screen which is vital when shooting photographs or video footage.

Historically the LED lights within mobile phones were very low voltage and created substandard lighting. The situation today is very different. LED flash creates what experts describe as a soft and more illuminating light. The ability to use this incredibly focused beam of light has made a huge difference to both photographic and video footage quality. Some of the main benefits of LED flash include:-

• Low energy consumption
• The size and shape of the LED bulb does not impact the efficiency
• LED lighting creates specific colours without using filters
• An LED flash component is relatively small
• Heat output is minimal, especially compared to historic lighting methods

So, there we have it, the use of LED lighting has been around for some time in the mobile phone that you carry everywhere. Recent developments in the technology have dramatically improved both photographic and video output. This is an example of modern day technology which is all around us, although very often we have no idea.

Are LED bulbs dimmer than traditional light bulbs?

In the early days there was some confusion regarding LED light bulbs and whether they were brighter or dimmer than the traditional incandescent lighting we all used in the past. While we can wax lyrical, the figures speak for themselves. Brightness is measured by lumens. Below we have listed the lumen output for a typical 25 W bulb in various forms:-

• Incandescent light bulb 200 lm
• Halogen light bulb 300 lm
• CFL lighting 1600 lm
• LED light bulb 2600 lm

So, the idea that LED light bulbs are dimmer than other sources of light is simply wrong. Using the 25 W bulb example above, an LED light bulb is 13 times brighter than an incandescent light bulb of the same wattage. It is fair to say the argument about dimmer LED light bulbs has been proven?

Why do LED light bulbs flicker?

As governments around the world outlawed old-style incandescent lightbulbs, in favour of LED lighting, many mistruths and simple lies emerged about LED lighting. One of the more common issues discussed in relation to LED light bulbs is a “flickering” effect. Do LED light bulbs flicker? Yes, but only as a consequence of fluctuations in your home power supply.

As LED light bulbs are so efficient – they light up as soon as you flick the switch – the variation in power supply is more visible. Whether a light bulb, television or any other electronic device, they are all susceptible to fluctuations in your home power supply. The only reason you don’t see any visible change in incandescent light bulbs is because the heat going through the filament masks any short-term fluctuations in power supply. These lightbulbs are still in receipt of fluctuating power but the flickering is not as visible as with an LED light bulb.

The highly efficient nature of LED lighting is the only reason why any fluctuations in power supply are more visible.

What is an LED light beam angle?

The beam angle associated with any form of lighting is simply the angle at which the light is distributed. You will notice that light sources such as incandescent lights, fluorescent lighting, etc make use of various materials and gases to enhance lighting. This means that the light beam angle is less controllable than when compared to LED lighting.

As an LED light is created as a consequence of two semiconductors, solid masses, this can be pointed in a particular direction. This makes LED lighting extremely useful when it comes to night-time reading and night-time driving. It is the pinpoint focus of the light beam angle which creates maximum efficiency and maximum visibility. The term light beam angle is not exclusive to LED light bulbs – it is a term used with any form of lighting.

What is CRI? (colour rendering index)

The CRI (colour rendering index) is a very interesting measurement of how particular light sources reveal the colour of objects, in contrast to natural lighting. The most common form of natural lighting is unfiltered sunlight.

The ranking on the CRI will relate to the level of lumens created by the light source. For example, relatively poor lighting will fail to illuminate objects in your room and as a consequence you will struggle to see their colouring. The range of the CRI measurement is impacted by the temperature of the light which can vary from ultraviolet light to infrared hot and everything in between.

As you can see from the chart below, a rating of 75 and above is reminiscent of daylight quality lighting. Traditional LED lighting has a score of between 80 and 90 which reflects the more natural looking light. While some suggest that LED lighting is more useful indoors, we have seen great strides made in the technology for use outdoors as well.

While you may look at the chart and wonder why LED lighting does not have a higher rating, why is this not beneficial? Well, if you think of a light source as varying between darkness and ultrabright, if the light source is too bright you will struggle to see anything. Therefore finding a balance between the 80 and 90 level is perfect for the vast majority of uses.

Why do some people say LED lights are blue?

One of the more common “criticisms” of LED lighting since it came to the mass market has been the mysterious phenomenon of blue lighting. While this is something of a red herring, thankfully it is an issue which the industry has tackled head-on. Perhaps we need to explain the whole concept of blue lighting. All white lights are composed of red, blue and green lights mixed in various ways. Therefore, any white light you see today, from a lightbulb, sun or anything else contains a degree of blue light. However, this is only a fraction of the wider colour spectrum.

The temperature of a lightbulb is directly associated with the degree of blue light. The cooler the lightbulb the more blue light is emitted. As LED light bulbs create but a fraction of the heat compared to incandescent light bulbs, the myth began to grow that LED lighting created huge levels of blue light. A number of research programs, often designed to undermine LED lighting, jumped on the bandwagon to suggest that blue lighting from LED lighting was potentially harmful to eyesight/general health.

The focus on LED lighting with these research programs failed to clarify the same level of blue light in other forms of lighting. In recent times we have seen the introduction of legislation designed to clarify low levels of blue light in LED light bulbs. Indeed, ongoing modifications to LED technology led to a reduction in blue light of 80% – compared to the earlier products available at the turn-of-the-century. Therefore, the myth that LED lighting somehow contributed to the emission of huge levels of blue light is now outdated. There were never any major problems but it suited the agenda of many to inject uncertainty and controversy into the use of LED technology.

What does colour temperature mean?

The colour temperature of a lightbulb is very important and is measured in Kelvins. In simple terms the higher the colour temperature, the cooler, more energising light which is emitted. Consequently, a lower temperature will produce a warmer more relaxing glow but this won’t be as bright as a high-temperature colour. The range for LED lamps is as follows: –

• Blue 10,000 Kelvins
• White 4,000 Kelvins
• Yellow 2,700 Kelvins
• Daylight 5,000 Kelvins

When considering the strength and power of a lightbulb, you will find that many of them are compared and contrasted against daylight. The range of LED lighting available today is absolutely huge. The technology has come on in leaps and bounds in recent years, hence the reason why we have seen a large take-up by businesses and consumers.

Do LED light bulbs look different to incandescent bulbs?

When you consider that the look of an incandescent light bulb simply relates to the exterior, this is easily replicated for LED light bulbs. Normally they will still use the same fixtures and fittings, still have the same shape but their efficiency and lighting capabilities are very different. In recent times some of the suggested replacement to incandescent light bulbs took an age to “warm up”. This is not the case with LED lighting which is instant. So, LED light bulbs and incandescent light bulbs will generally use the same fixtures and fittings and look the same.

Will an LED light change the colour of my room?

There is a common misconception that LED lighting is more efficient but not as “colourful”. In the past, prior to significant advances in the technology, this may well have been the case. Today, it is very different. Aside from the 90% saving in energy use, LED lighting is more focused, more manageable and available in warmer/cooler colour temperatures (see above). LED lighting will give you the same colour in your room but you will have more control. There is even what is known as “smart” LED light bulbs which you can control wirelessly. If anything, LED lighting gives you greater control over the colours you want to show in your room.

What is an integrated LED?

As LED light bulbs use solid state materials, they are more flexible than traditional incandescent lighting. It will be no surprise to learn that you can now acquire integrated LED fixtures where the LED lighting is built into the fixture. The LED lighting in these products is not a stereotypical LED light bulb and not so easy to replace. However, as we mentioned above, the many benefits of LED lighting include the massive extension in life. As a consequence, an integrated LED light fitting will last for many years, very often in excess of a decade. This type of product has not always been cost-effective when using incandescent lighting technology.

Integrated LED lighting is a sector which is also in its relative infancy. While we have seen huge development of the technology in recent years, there is far more to come. The fact that LED lighting can often last in excess of a decade perfectly illustrates the huge potential benefits. This is an area of the market which has attracted huge attention from consumers and businesses. Integrated LED lighting would appear to be the way forward!

What is an L80 LED light?

When looking at LED lighting you will come across various standards one of which is L80. Strictly speaking, the standard may be described as L80B10 (as one example). So what does this mean?

The L80 element confirms that 80% of the luminous flux (the lighting element) will be maintained for a defined period of time at a particular temperature. This is effectively a guarantee that up to a predetermined time, for example 50,000 hours the lightbulb will still be omitting a minimum of 80% of its original “brightness”. The B10 description means that a minimum of 90% of the luminaries will be less than 80% of the original brightness at the 50,000 hour mark. We have put this into layman’s terms because there are more technical descriptions but this is effectively what it means.

Why are LED light bulbs better than CFL bulbs?

Before we continue, the term CFL relates to a compact fluorescent light bulb. It is a term that you will come across on numerous occasions when comparing and contrasting LED lighting with incandescent bulbs and CFL bulbs. There are a number of factors to take into consideration but most focus is placed upon energy efficiency and the working life of a bulb.

When you consider LED lighting uses up to 90% less energy than their incandescent/CFL bulb counterparts, this says everything. Not only does this assist with electricity bills but there are also huge benefits to the environment. Traditionally, halogen light bulbs will last around 3,000 hours, CFL bulbs up to 10,000 hours but LED lights beat these numbers hands down, lasting up to 50,000 hours. Based upon average usage an LED lightbulb will last 11.4 years!

What are smart lights?

While the concept of smart lights is not necessarily new, the way in which LED lighting fits into this category has been a game changer. Smart lighting is basically a light which can be controlled by a remote device such as a mobile phone app. These can prove extremely useful when it comes to issues such as security and simply adjusting your lighting without leaving your seat. As LED lights are based upon solid materials, as opposed to gases used in other lightbulbs, they are easier to control and extend remote functionality.

As a consequence of LED technology, not only can you dictate when the light comes on and goes off, but you can control brightness and the colour that it creates. If you sit back and think for a second, this added functionality opens up many potential uses going forward. Watch this space!

What are lumens?

The best way to describe lumens is a measure of the amount of visible light from a lamp or other light source. When we say “visible light” we mean visible to the human eye. In simple terms the higher the lumen rating the brighter the light. This is an area where LED lighting is simply streets ahead of the competition – as you will see in the following table:-

Lighting type	250+ lumens	400+ lumens	700+ lumens	900+ lumens	1100+ lumens
Incandescent	25W	40W	60W	75W	100W
Halogen bulb	18W	28W	42W	53W	70W
CFL	6W	9W	12W	15W	20W
LED	4W	6W	10W	13W	18W

It is not difficult to see why governments around the world withdrew incandescent lighting from the marketplace, encouraging the use of LED lighting. The huge difference in energy usage, without affecting the lumen rating, is there for all to see.

Can LED bulbs be used with dimmer controls?

The simple answer is yes, LED light bulbs can be used with dimmer controls. What you will find is that the vast majority of LED light bulbs will require specific dimmer controls for LED lighting. As with traditional light bulbs, there will be some LED light bulbs which are not suitable for use with traditional dimmer controls. The reason why some LED lightbulbs are not suitable for traditional dimmer controls used with incandescent light bulbs is simple, they work on lower wattages.

As a consequence, the minimum wattage control on a traditional dimmer switch would not be low enough to dim the LED light as required. In effect, LED light bulbs use but a fraction of the energy required for incandescent light bulbs. As a consequence, the required minimum/maximum wattage range required on the dimmer controls is very different.

Will LED light bulbs work with my current light fittings?

As all lightbulbs work on the same principle, using a current to create heat or in the case of LED light, activate light emitting diodes, in many cases it is simply down to the fittings. When governments around the world began to clamp down on incandescent light bulbs, in favour of LED lighting, there was a need to maintain current light fittings. As a consequence, the majority of LED light bulbs available today are created in the same design and able to fit into historic light fittings.

There are some specialist LED light bulbs out there, and you would need to check the specifics of each lightbulb before using it, but in general, using LED light bulbs with your current light fittings should not be a problem.

How long do LED light bulbs last?

When considering the life of an LED light bulb, it is important to compare and contrast with incandescent light bulbs, halogen light bulbs and CFL lighting. In layman’s terms, an LED lightbulb lasts around 50 times longer than an incandescent lightbulb, up to 25 times longer than a typical halogen light and approximately 10 times longer than CFL lighting. The average LED light bulb will last around 50,000 hours which equates to more than 11 years if used 12 hours a day. If you use your LED light bulb eight hours a day it will last 17 years.

Aside from the fact that LED light bulbs are far more efficient than any other form of lighting on the market today, it is their durability and long lasting life which makes them extremely attractive. Historically, there were some issues with LED lighting and the range of colour and brightness available, but these are a thing of the past. LED lighting is comparable with the quality created by any other form of lighting available on the market today (and even those banned by governments).

Can I use LED lightbulbs with a remote control?

The simple answer is, yes. As LED light bulbs are “solid-state lighting” which use semiconductor light emitting diodes, they are extremely responsive when used with remote controls. While other forms of lighting will involve the use of various gases and reflective materials, LED light bulbs are far more manageable. You will also come across an array of apps available for your mobile phone which will allow you to control LED lighting from a distance.

It is fair to say that the introduction of LED lighting to the mass-market has made a huge difference, opening up many new avenues for the future. Even though the industry has been around since 1907 in some shape or form, recent technological advances would appear to be still in their relative infancy. We can’t wait!

Do I need an LED compatible transformer/driver?

There are some matters to be aware of when it comes to LED lighting, one of which is compatible transformers/drivers. This is simply a means of reducing the mains voltage output to the required low-level for these highly efficient light sources. Thankfully, the vast majority of LED lights will already have the transformer/driver built into the bulb casing and there is nothing more to do.

There may be situations where you require a constant voltage lead driver with a 12 V/24 V DC output. For example, if you are powering LED tape or LED ground/marking lights you would probably require an external transformer/driver to control the mains voltage. These are issues which will be made clear when you acquire such LED lighting. We are not talking about big transformers/drivers but simple devices which will reduce voltage output from the mains so as not to overpower/burnout the LED light.

What are SMDs? Surface mounted device/Surface mounted diodes

There has been huge progress in the area of surface mounted diodes/surface mounted devices in relation to LED lighting. This is a type of technology where the light emitting diodes are mounted on an aluminium substrate and kept in place using an epoxy resin. When you consider the size of the actual LED lighting element, compared to for example an incandescent lightbulb, there are potentially endless uses. Whether you are looking towards LED lighting on the ceiling, kitchen work surfaces or even in a games room, the options are plentiful. The old days when an LED light used to “warm up” before emitting light is long gone. The technology before us today bears little or no resemblance to that of just a decade ago.

Summary

The rate of development in LED lighting technology over the last decade or so has been unbelievable. Even though this type of technology has been around since 1907, it was only in the 1960s that it began to be used for potentially mass-market lighting requirements. Since various governments around the world began to phase out incandescent lighting, as a consequence of energy efficiency and environmental issues, there has been a huge uptake in the use of LED lighting.

This has attracted enormous investment in the industry, leading to great paces forward with the technology and the realisation that the sector is still in its relative infancy. The future is exciting, the future is LED lighting!