Category Archives: Technologies

There are a spectrum of technologies used in energy saving light bulbs. This category looks at the technologies used today and for the future

How do LED’s actually work?

It is true, LED’s can save you a lot of money, but some of you might be wondering how LED’s actually work; this article is going to go into more detail about the technical side of LED’s and show you how they work. But be warned, it could get very scientific!

LED’s actually stand for Light Emitting Diodes; now diodes are the important factor in this. You may have heard of diodes before, they have actually been around for a long time, but their use with light is a newer development. A diode is an electrical component that allows electricity to flow through it in one direction only.

junction diode

A diode contains two types of silicon – a p type and an n type (if you look at the diagram above it identifies them as red or green). When you combine them this becomes a junction diode because the extra electrons and holes that both the p type and the n type contain, will swap so normal silicon can start forming again. There is a gap in the middle of these though which is called the depletion zone where no electrons or holes enter.

There are type types of junction diodes, a forward-bias or a reverse-bias. These different junction diodes occur when you attach a battery to the junction diode. When you attach the negative end of the battery to the n type silicon, the depletion zone between the p type and the n type shrinks, electrons and holes move across in opposite directions and a current flows; when this happens it is a forward-bias. The diagram below indicates some of the electrons from both the n type and p type have moved across.forward bias

The opposite current is when the negative battery is attached to the p type, when this happens the depletion zone gets wider and prevents current from flowing. This is called reverse-bias. The opposite of what happens in a forward-bias happens here (shown in the diagram below).reverse bias

It is only through a forward-bias current that LED’s actually light up; the light comes from the electrons and holes moving around – when an electron combines with a hole, it disappears but creates an atom which becomes stable and gives off a photon of light.

So to summarise, LED’s are diodes that are designed to emit light. At different wavelengths, LED’s can also be red or blue; for red LED’s you would need between 630-660 nanometres wavelength and for blue 430-500 nanometres wavelength. It was in these colours that LED’s were originally, but the technology has been developed for them to be available in white light now too. LED’s can also make infrared light so are often used in smoke detectors or intruder alarms.

red leds

LED’s have been designed and developed to be the better source of light in a variety of different ways;

They are:

  • Rounded plastic bulbs to make the light brighter and more concentrated.
  • Small and relatively inexpensive.
  • Easy to control electronically.
  • Long lasting.
  • Save a lot of energy because they don’t get hot.

What are you waiting for? You have learnt how they work, you know how much they can save you money, so why haven’t you converted yet?! For any more questions or more information, please don’t hesitate to get in touch!

led

LuxLive 2015

luxlive logo

For the first time, SLB decided to be a part of the Lux Live exhibition which happens annually at the ExCel centre in London. It is Europe’s biggest lighting exhibition which attracts thousands of professionals who come to learn more, see more and get inspired! We thought that we had to partake in this exhibition at least once! And we are so glad we did; LuxLive 2015 resulted in being the biggest exhibition to date with over 300 exhibitors and at least 7000 attendees. The exhibition as a whole saw an increase of 5% on previous years! (… we’d like to think that’s because we were in attendance!).

LuxLive is an “an unrivalled showcase of the best the industry can offer in terms of the latest technology, developments and expert thinking”. It is an exhibition where people go to get better ideas, find out how they can save more energy and money and how best to make the most of lighting in their specific area of interest. It has been awarded the Best Trade Launch Show by the Association of Event Organisers, which just proves how successful and useful many find it!

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The great thing about the exhibition is that it tackles lighting issues that people in different sectors will be having difficulties with and wanting solutions for; there are people and exhibitors from all different sectors who represent lighting from areas such as retail, the workplace, hospitality and leisure, education, healthcare, industrial, outdoor and street, transport, residential developments and emergency lighting.

Within the days of the exhibition, there are also discussions that the attendees can participate in to get their ideas across while also hearing from other people’s ideas. Bigger companies who have previously experimented with ideas and lighting techniques will also present case studies to portray what worked well and what didn’t in putting some of these ideas to practice.

lux life

The exhibition gives many the opportunity to learn about the latest technologies that can be used in the different sectors, and hear about them from peers who have put it into practice and can tell you more about it! There is always the fear and concern that switching your lighting can change an atmosphere or lessen the desired effect of usage in the workplace, school or other areas which rely of lighting to function. This doesn’t have to be the case though and it is at LuxLive that you can find this out and learn so much more – widen the horizons so to speak.

It is an exhibition which gives! Gives information, helps you save money on your energy bill and simply wants to help give you the knowledge on how to better your lighting for your professional environment!

The exhibition also gives to the exhibitors as well as the attendees; as exhibitors, we too were also able to discover new and exciting developments that are happening in our area, see from competitors, how they do things differently, while also making connections with other people in the same sector to work together ensuring customers could get the best advice and products they were looking for. All in all, we realised why it is such a popular exhibition!

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We were fortunate in the positioning of our stand as it was a corner one which meant that attendees would often meander into our stand to see what we were advertising and keen to show off! Our sister company Classical Chandeliers were also with us to add some sparkle to our stand and show off what they also offer.

DSC_6943The main attraction was our lady; who sparkles and causes a stir wherever she goes! Especially to designers who are interested in something different which is unusual but at the same time mesmerising! We were very thankful to have her manning the stand with us at LuxLive!

 

2D LED Emergency Light

The 2D LED in more detail

The 2D CFL lamp has widespread use across a range of application primarily in commercial buildings. It is most generally used for functional lighting purposes where the decorative side is of little concern but good visibility and reliability is of paramount importance. One example is car park lighting where 247 illumination is important and also a high level of reliability. In this case the 2D LED  outperforms its predecessor the 2D CFL due to its very long life, typically over 30000 hours,  and also its high efficiency, using around half the energy of the CFL lamp.

The case then becomes stronger when considering applications like corridor lighting in residential homes where illumination is key but to save energy  the majority of the lights are switched on movement of heat activated sensors to light up on demand. This is an excellent way  to use 2D energy saving light bulbs but one problem with the CFL is it does not react well with repeated switching which will invariably lead to premature lamp failure. For this reason the 2D LED is often selected which is far more tolerant to repeated switching and this does not effect the expected life span.

The 2D Emergency Lamp

2D LED Emergency

The other key factor about a high number of applications for 2D lamps is that it is critical that there is level of illumination in the area for safety reasons in all situations. This means that it is critical to have an adequate level of light emitted in the eventuality of a power cut. It is no good if you are trying to negotiate a corridor in the middle of the night in pitch darkness! For this reasons the regulations for commercial buildings often stipulate that an emergency back up light is needed which will operate for a period of 4 hours. In order to satisfy this criteria the lamp must detect the loss of power and then switch over automatically to the emergency back up.

This is another area where the 2D LED Emergency Lamp scores very high as it only consumes around half the power of the CFL lamp and accordingly only needs half the ampere hour rating for the battery back up system. The way this 2D LED emergency light works is to have a set of 6 dedicated LED’s in the centre of the lamp which are lit under battery power in the event of a power failure. The lamp has a small external driver system and a separate battery unit which is supplied with the system which can both be fitted into a normal 2D lamp fitting. This way somewhat unreliable 2D CFL lamp can be revitalised to perform as a highly efficient, 2D LED Emergency Light with an exceedingly long life. Even with continuous operation the expected life is 3-4 years!

It has been possible previously to utilise an emergency backup LED driver to drive a conventional 2D LED in emergency situations.  However, this can be a very expensive solution so the emergence of this fully integrated system is a real plus from a total cost of ownership perspective.

Advice on dimmable LED drivers

Do you need LED Drivers?

If you are changing your MR16 12volt halogen lamps to MR16 LEDs then you will undoubtedly wonder whether you need to buy specialist drivers. The LED driver suppliers will most probably say you do but clearly they have a vested interest in making a sale, but the answer lies in the technology inside your LEDs. If the LED MR16 has an internal driver that can accept both AC and DC input of 12 volts then you do not need the LED driver however conversely if it does not have the internal driver it will normally work with a standard halogen transformer but you will see inefficiencies and a reduction in lifespan. To add more the reduction in life is normally quite drastic, of the order of 50% so do check the specification of the LED MR16s ideally before you purchase them. LED drivers are not cheap so it is always worth purchasing LEDs with internal drivers as the overall cost of service will be lower. However this is just the case for non-dimmable MR16 LEDs and the dimmable variety are more complex so please read on.

Dimmable LED Drivers

If you are investing in the dimmable LED MR16 then these are far more sensitive to the choice of driver and indeed the dimming switch. LED lamps use very low currents and accordingly the drivers need to operate at very low wattage which generally requires a specialist driver. If you run a dimmable LED of a standard halogen dimmable driver then the chances are it will flicker which you turn it down and it will not operate smooth whilst you dim the lamp. This is primarily because the halogen dimmer is designed to operate at higher wattage so one way to overcome this issue is to put a dummy lamp or resistance in parallel to the LED so increase the load. This can often work but then you are burning energy to run the dummy lamp which is then negating the benefit that you would have  accrued by moving to LEDs in the first place!

So the best solution is to use a specialist dimmable LED driver and compatible dimmer switch.  The best way to go about this is to actually purchase drivers and dimmers that are compatible and tested with the lamps as this way you can be assured that the operation will be satisfactory. However if this is not possible then there are some steps worth taking. Firstly, check the VA rating of the dimmer and try to make sure that the total loading from your LEDs is just less than this rating. For instance if you have a 20VA LED driver and 6W LED MR16s then it would be best to use 3 lamps. The second step is to ensure that you use a dimmer switch which can operate in the range of the total loading of the sum of the LED wattage that it is controlling. So these are 2 good guidelines but I would still recommend that you do a test before investing or check there is a return policy.

For these reasons we have elected to offer a dimmable LED driver which is compatible with our MR16 LEDs as this can save a lot of pain.

 

2D LED lamps their uses and benefits

Background to 2D Compacts or 2D lamps .

The 2D lamp has been around for some time now and has widespread usage especially in commercial applications. They are compact and high brightness and the only real alternative is the tube light. The benefits of the 2D compact or 2D lamp is that it fits into remarkably reasonable looking bulkhead and ceiling mounted fittings which are of a compact size and easy to position in a multitude of places. For this reason they have become very popular for car parks, corridors in flats, warehouses, storage facilities, offices, hotel work areas and a host of other commercial applications. They are often fitted with passive infrared sensors ( PIRs) so they just light up on demand when somebody passes the sensor.

The standard Fluorescent 2D compact and some if the drawbacks compared to the 2D LED lamp.

The normal lamp fitted into the 2D bulkhead fitting is the fluorescent 2D compact which generally some is sizes of 16, 28 and 38 watts and with either 2 or 4 pin connectors. The fluorescent 2D compact is a good lamp however does have a few drawbacks. Firstly these light fittings are often controlled by PIR’s and the fluorescent lamp by its nature is not suited on repeated switching on and off and this normally leads to premature failure which means that a 2D compact lamps with a rated life of 10000 hours may only last 2500 hours! In contrast the 2D LED uses an improved technology which means that rapid switching is not an issues so you will not see a reduction in the life expectancy.

Also 2D lamps are often on for very long periods.  As an example in a car park they would typically be lit 24 hours a day and with this level of usage you would only get around 1 year life from a 10000 hour unit. Also if the lights are fitted in critical places and there is no back up lighting then failure can be a major issue so the longer life of the 2D LED is especially beneficial.

Additional benefits of the 2D LED lamp

dimmable energy saving light bulb

The 2D LED lamp has a lifespan of around 35000 hours which is typically 4 times longer than its CFL counterpart.  This means that not only will failures be avoided and the disruption that they cause but additionally there is less maintenance cost for making the lamp changes. If the 2D compacts are in light fittings which are in important areas then it will often be necessary to either fit more light fittings so that there is redundancy in the system but consequently you can accept a few failures or use the 2D LED lamps which mean that you will get much higher reliability.

The 2D LED lamp has a directional capability typically with a beam angle of 120 degrees. As a consequence you can direct the light straight out of the light fitting as opposed to with CFL 2D lamps where there is a lot of wasted light which is cast back into the fitting and if this is not reflected out just servers to heat up the unit. As a consequence the level of light in the area LUX will be higher using the 2D LED lamp than the CFL 2D lamp. As an example the 2D LED 4 pin 14 watt will provide better illumination than the 28w CFL version.

The 2D LED lamp has its own built in driver and as a consequence does not need an external ballast or driver. This means that you will experience no failures doe to the light fitting ballast failing.

The dimmable energy saving light bulb

The Energy Saving Light Bulb

The energy saving light bulb has developed in leaps and bounds over the last few years. The CFL ( compact fluorescent lamp) technology that they use has had a few issues in the past. Firstly, the older CFL energy saving light bulbs took a long time to reach their full brightness and when I say a long time I mean of the order of 20 minutes. This meant that they were quite user unfriendly certainly when people were walking between rooms for example showing guests around. Secondly, they were not  dimmable which meant that people who had a dimmer fitted in a space for mood lighting considerations no longer could use that facility.

The dimmable energy saving light bulb

The dimmable energy saving light bulb has always been around but can suffer from a number of setbacks. Dimming the CFL technology lamps is not a trivial issue and many of the dimmable CFL lamps do dim but not progressively and will not reduce much in brightness. As a consequence you can reduce the brightness but only in steps as opposed to in a progressive manner. With out CFL lamps we actually supply UK dimmer switches to the manufacturer so thay these can be used as part of the testing process and in this way you can be assured of a good product.

dimmable energy saving light bulb

Another issue has always been the price of the dimmable energy saving light bulb which is a result of the complexity if the electronics inside and also the extensive testing processes they need to go through to ensure compatibility with a broad range of dimmer switches and high end dimming systems for instance Lutron. There is no easy solution here but the prices have reduced and it is all about finding a dimmable light bulb that is of hogh quality and reasonably priced. It is unlikely that you will need to put dimmable energy saving light bulbs all over your house so they higher investment needed for those rooms where you need the mood lighting is generally considered to be a sound investment.

Another important consideration is that a number of dimmable energy saving light bulbs on the market are not very high powered. Typically they tend to be up to 20 watts and producing somewhere around 1000 lumens of light output. If you are having a dimmable bulb then it is generally much better to purchase a bright one on the basis that you can always dim it. Unlike with the old fashioned dimmers, which used a rheostat which meant that you did not see an energy saving when the light was dimmed, modern triac systems do mean that you save electricity when the light is dimmed. Consequently it is always best to go for a high wattage CFL lamp of high lumens output. Our lamps are 25w watts and produce 1400 lumens output so you can enjoy a high light level but progressively reduce the level when the mood takes you!

How to install LED Tubes

Why is installation different with LED Tubes and Fluorescent Tubes

A fluorescent tube has its own ballast which can either be of the inductive or electronic type which is used to drive the tube itself.  In a standard energy saving light bulb of the CFL type this is actually contained within the bulb itself but with traditional fluorescent tubes this is normally separate and located inside the light fitting.

Conversely with our  LED Tubes the driver is actually part of the LED tube itself  so the LED tube is a totally integrated stand alone unit which can simply be wired up to the mains.  This means that if you are fitting an LED tube to a conventional fitting then you need to make a few simple modifications to the wiring.

How to fit an LED tube to a conventional fluorescent tube fitting

There are 2 types of circuits normally use which are either

1. Exisiting installation with starter and inductive ballast

2. Existing installation with electronic ballast

Here is a graphic illustration showing the modifications necessary for the 2 types of installation.

LED tube installation

Please click on the image for a larger view.

In simple terms if you have a fluorescent tube fitting with an old fashioned starter you can simply remove the starter  and then short circuit the connections across the inductive ballast. This will take the inductive ballast out of the circuit and mean that you have mains voltage applied to either end of the LED tube. The LED tube will then  light up correctly.
Alternatively if you have a fluorescent fitting with a electronic ballast then you need to remove this from the circuit. This can be simply done by cutting the wires to the electronic ballast and connecting the mains neutral to one end of the LED Tube and the mains live to the other end. The LED tube will then operate correctly.

So to summarise with an LED tube you simply need to connect the mains live to one and and the mains neutral to the other and it will then operate. This is much simpler than with the old style fluorescent tubes and in time the lighting fixture suppliers will provide holders which work directly with LED tubes. These will in fact be a simpler design so in theory an LED tube light fitting should be cheaper than a conventional fluorescent tube holder.  But watch out to make sure that the manufacturer do actually charge less!

Once you have converted your fitting to take an LED tube then I would imagine you will never look back, but if you want to convert back then just keep the starter and these notes and you will be able to revert back to the old set up.  If you have a lot of fluorescent tubes then you will potentially want to convert them all. First try one and once this is up and running you should be able to tackle the others in the same methodological fashion and change the set in a rapid succession. And don’t forget that this time invested now will reap rewards in the future because an LED tube will last typically 5 times longer than a traditional fluorescent tube so you will  not have to keep changing the ones that fail.

The CFL downlghter- An alternative approach

The  options for downlighter with Energy Saving Light Bulbs

The halogen downlighter has taken hold in the kitchens and work areas of today’s households and it is here to stay!! The halogen gu10 and the halogen mr16 spot lamps have made their in roads into the home and with their path they have left many holes dotted across the ceilings!!  Now they are very functional and practical but the over powering argument for their continued existence is the fact that it would be prohibitively expensive to fill all these holes and skim the ceiling with plaster! So what we will so here is look at some of the options moving forward.

Energy Saving Halogen GU10 lamps

Now probably the simplest and least investment alternative is to replace your 50w halogen GU10 bulbs with the  energy saving halogen GU10 which will actually give the same light output but deliver at least a 20% saving in electricity. This is simply due to the use of energy saving halogen technology which is not expensive but works incredibly effectively making this a very viable quick fix for the very high electricity bills.

Energy Saving CFL Downlighters

The halogen energy saving light bulbs will have a positive impact on electricity consumption but if you want so save serious money then you need to step up a level to the compact fluorescent lamp – energy saving MR16 or energy saving GU10 . These use the CFL technology which will save around 80% when compared to a conventional filament bulb. As a consequence then a 7 w energy saving CFL will produce the equivalent light output to a 35w halogen and the 11w version will produce the equivalent output to an 11w version. This is a considerable saving and the MR16 spot lamps are nice and compact so they will fit into conventional fittings as a retrofit light bulb. One thing you need to look out for is the transformer specification for the MR16 units as these can be quite particular and in general it is best to use a matched transformer supplied by the lamp manufacturer.

The energy saving GU1o is efficient also but the length of the lamps is longer so you can either have it protruding which is fine as the protruding portion is silver coloured or alternatively you can change the fittings for some longer reach units.

Clearly the other alternative if the LED MR16 or LED GU10 which are far more efficient in energy consumption saving around 88% when compare to conventional filament light bulbs. However, the disadvantage with the LED is twofold. Firstly they are more expensive, and secondly, they are not as bright. If you can accept long reach bulbs then you can purchase units which have the same brightness as the 11w MR16 CFL energy saving light bulbs but if you want to simply replace your 50w halogen MR16 bulbs then the 11w CFL MR16 has got to be a very cost effective solution. The day will certainly come when the LED will undoubtedly take over and the CFL just be a technology used at a point in time in history but we are certainly not there as yet.

Advancements in LED GU10 and LED MR16 bulbs

Background

Things have been moving really fast in the LED GU10 and LED MR16 world! Every few months the technology is advancing and the manufacturers are improving their production processes and as a result the products are getting better and the costs have reduced significantly. It was just a year ago when the 3W LED GU1o or MR16 was about the limit of the technology for producing LED bulbs at a realistic price. For sore your could get 5 and 6 watt products but the price was typically £20 or £30.  The 3W LED is good and typically can generate around 200 lumens certainly for the multiple LED bulbs which if you are replacing 25w or 35w halogen lamps is just fine but if you needed to replace 50 watt halogens  then your options were limited. The other issue with the LED MR16 and GU10 bulbs is that they generally were not dimmable which actually is often fine for a low lumens unit but as the brightens increases then it can be beneficial to have dimmable GU10 and MR16 LED bulbs.

The applications for LED GU10 and LED MR16 spot lamps.

People invest in LED bulbs primarily to save money on electricity, enjoy much longer life for the lamps and play their part in helping to preserve the environment. However, the investment can be for different reasons, specifically:-

1. A requirement to exchange existing MR16 or GU10’s for commercial and environmental reasons.

2. A new build, or refurbishment where new light fittings and light bulbs are being purchased to achieve the right illumination for a space and minimise running costs and make an eco statement.

If you are involved in a new build or major refurbishment  then this gives more options when it comes to bulb specification. In this case a state of the art dimming system like a Lutron would typically be installed to bring on the lights gently and to provide total flexibility for getting the right mood lighting. To complement these 50W equivalent GU10’s are often fitted certainly to kitchens and work areas which clearly would need to utilise the dimmable capability. Here the options are greater for LED’s because longer depth light fittings can be purchased which means that you can use a longer GU10 lamp say of 80mm length as opposed to the standard which is around 50-60mm. There are a number of these longer lamps on the market which are typically 6 watt or 7 watt which have the dimmable technology so your options are not restricted.

LED GU10

Conversely if you are involved in a straight exchange for your existing 5o watt halogen bulbs then the constraints are tighter. In this case you need to get a MR16 LED dimmable or a GU10 LED dimmable bulb that has the right proportions for your light fittings. This means that you generally need a lamps which is a maximum of 60mm long. This is where this MR16 LED dimmable bulb or alternatively if you need a GU10 this GU10 LED dimmable bulb is an ideal choice. This spot lamp has 3 x 3watt LED’s but there power loading is reduced on the lamp so that the light output is maximised but the heat output is kept to an acceptable level for this size of unit. Also the light bulb uses advanced dimming technology for that the lamp can be reduced in brightness for the the desired mood effect for the space. So all in all this spot light has the advantage that it is a perfect choice for a light bulb exchange to save on electricity bills but in addition is also a good choice for a new build or major refurbishment. This has got to be a winner!

Measuring Light Bulb Brightness

When we just had incandescent light bulbs, getting a good indication of  the brightness of the bulbs was quite straight forward. People just used to use the light bulb wattage as the brightness measure. So people would say, ‘this room needs a 60watt bulb’ or ‘this room needs a 100watt bulb’. Importantly, wattage is not a measurement of light output it is a measurement of power consumption, but as all light bulbs used the same technology this measure proved to be a good brightness indicator. In fact, it almost turned into the universal measure nearly achieving the level of accreditation that a British Standard would!

Now this is all well and good when you only have just one technology, but the plot thickened with the emergence of the fluorescent tube because an 18watt fluorescent tube produced far more light output than a 100 watt incandescent light bulb. Clearly we now need to understand light output in more detail and use more sophisticated light measurement techniques now that we have a spectrum of different light bulb technologies. As an example a 60watt incandescent bulb will produce the same light output as a 15watt CFL but it may only require a 40 watt halogen bulb or a 10watt LED to produce the same light level in a room! The other complexity is the light bulb cover. With traditional bulbs a clear bulb would produce more light than a pearl one and in a similar way, with modern CFL light bulbs a 15watt globe will produce less light output than a 15 watt spiral CFL. This is because the global bulb is manufactured by producing a spiral CFL and then putting a glass global cover on it to give the aesthetic design character. Obviously the cover will absorb some light a and as a consequence the brightness will be reduced.

The Lumens light output measure

The simplest and arguably the best standard measurement of light output is the lumens measure. This is a straight forward measurement of the light intensity as perceived by the human eye. This means that it is a very good light output measure as it is adjusted to take into account the different sensitivity the human eye has to different wavelengths. So in summary, the lumens is a measurement of the total light output from a source and generally the base way to compare the light output from from different light bulbs.

Maeasurement of Light Level in a Room

Quite often you need to specify a light level within a room which is needed for the purpose that that room is intended for. As an example in an office area or a workshop or indeed in a kitchen the level of light is clearly fundamental, This can be specified by stating the lux value which is a known as the illuminance. Lux is simply a measure of lumens flux on a particular area. So as an example if 500 lumens were concentrated onto an area of 1 square metre then this would correspond to an illuminance level of 500 lux. It is not a straight forward process to convert from lumens to lux as the lux illuminace level will be a function of a whole range of factors, for instance, the geometry of the light bulb, the wall material and  the colour of the room. Architectural lighting specialists or lighting suppliers  will typically have formulae to provide guidence on what type of light units and lumens output will be needed to provide a lux level within a room.

The Candela

MR16 CFL Bulb Certain types of bulbs like spot lights produce a directional output and certainly with reflector bulbs the intensity of the light will be a function of the angle of the reflector and the corresponding beam. This is where the candela (cd) unit assists as it is a measure of luminous intensity, which is basically the brightness of the beam in a particular direction. If a light source produces an output of 1 candela uniformly in all directions it will produce 4 Π , which is approximately 12, lumens output. By example if  this was restricted to only produce output across half the area, a hemisphere, but still at 1 candela it would only produce half the lumens output. This means that this measure is particularly useful in measuring the lighting effect produced by light bulbs with reflectors, LED MR16 Bulbs and the  halogen spot . If the angle of the reflector is reduced the light intensity and accordingly the candela (cd) value will increase, but the lumens value would remain the same.