Frequently Asked Questions: LEDsHow does an LED work?
LED's are semiconductor diodes which work through an electronic chip by creating a positive - negative junction (or p-n). Once power is provided to the diode, a current flows from the anode (positive) to the cathode (negative). Electrons and electron holes then flow into the junction from electrodes, so when an electron meets a hole it creates a lower energy level providing energy as light.
LED's can come in various colours which are created by the materials used to make it. For example; white light can be created by using a blue LED and coating it with yellow phosphor or with a combination of RGB light (red, green and blue).
Why should I buy an LED lamp?
LEDs are more energy efficient than normal halogen bulbs (around 90% less) and combined with the rising electric bills, you can be saving money as the average household's electrical usage is just under 10% just for lighting and reduce your carbon footprint (see cost saving example). Around 90% of the electricity consumed by an LED is converted into light, whereas a standard bulb only converts around 15%.
Are LED's costly?
Overall, the cost of having an LED lamp is cheaper due to their low energy emissions creating low running costs, but their initial cost compared to a standard bulb is considerably higher (again, see cost saving example).
Where is it appropriate to use LED lamps?
LED lamps should be used when powerful directional light is needed such as spot lights, flood lights, track lighting etc...
Good for the environment?
LED's, as previously mentioned are very energy efficient and reduce carbon emissions quite considerably. They are also ROHS compliant and mercury free unlike other energy saving bulbs which contain a high amount of mercury and phosphor which can be a health hazard. Therefore, overall better for the environment than standard bulbs.
What's wrong with other low-energy lighting (CFL) for instance?
Many consumers have made a genuine effort to reduce their energy consumption and save money in the long run by using Compact Fluorescent Lights (CFL's).
Although 'CFLs' are seen as the "green alternative" to incandescent with their 10,000 hours lighting and provide the same amount of light as a normal lamp, CFLs still have their disadvantages. Many take a long time to warm up to the optimum light output and tend to flicker, you may also find that you get other types of light radiation and glare emitted from them that many people find uncomfortable
The biggest issue with CFLs is their requirement of various chemicals to allow their efficient performance. CFL lamps contain both phosphor and Mercury. These chemicals are hazardous to human health and the environment (Mercury has been banned from most electronic components). CFLS also tend to be made of glass so present an obvious health hazard of broken glass if they shatter whilst in use or when being disposed of.
In Actual fact you now must make special arrangements when you want to dispose of CFL's
Please see below recommended action to take if a Compact fluorescent light shatters …..
Got A Broken Bulb?
If a compact fluorescent light bulb breaks, you can't simply clean it up as you would an incandescent, because of its mercury. The U.S. Environmental Protection Agency says you should take these steps: Open windows and doors and walk out of the room for 15 minutes. Don't vacuum. On hard-wood floors, wear disposable rubber gloves and use cardboard or stiff paper to scoop up debris. Then clean the area with a damp paper towel. For rugs, use sticky tape to pick up any CFL fragments and powder. Place the debris and cleanup materials in sealed doubled plastic bags. Recycle if possible. After vacuuming the spot, remove the vacuum bag and seal. Put in a plastic bag, seal and throw away. Wash hands.
Source: Chicago Tribune
This was found by our MD on his recent trip to Canada in Globe and Mail newspaper but the advice was similarly given earlier this year in an article by the BBC;
A vacuum cleaner should not be used to clear up the debris, and care should be taken not to inhale the dust.
Instead, rubber gloves should be used, and the broken bulb put into a sealed plastic bag - which should be taken to the local council for disposal.
Unbroken used bulbs can be taken back to the retailer if the owner is a member of the Distributor Takeback Scheme.
Otherwise, many local waste disposal sites now have the facilities to safely collect and dispose of old bulbs.
Source: http://news.bbc.co.uk/1/hi/uk/7172662.stm
We would strongly recommend that you never use CFL lights in your kitchen or where food may be prepared!!
LEDs have none of these problems do not contain glass, and are fully recyclable.
What is mercury?
Mercury (Element number Hg)is a toxic metal, like lead but liquid at room temperature and is dangerous to humans however they come in to contact with it. A normal CFL lamp contains around 4-6mg of mercury.
Can LED lamps be used in existing light fittings?
Most LED bulbs work in standard light sockets and can be easily fitted as like any other bulb due to their same fittings as normal bulbs, i.e. GU10, MR16, E27 etc..
How is the lifetime of an LED determined?
The lifetime of an LED is estimated by the time that the LED only emits 70% of its original lumen output but it will continue to light after its potential lifetime.
Do LED's give off any heat?
LED's use heatsinks to move heat away from the LED junction to allow the LED to remain at room temperature, although this means that the heatsink may get hot.
What is the light quality of an LED?
LED's produce a cleaner light quality than a standard bulb as there is no radiant glare from them. The brightness of the LED is determined by both the colour temperature and lumens. As the LED's are directional the light they create is focused on where you want it, not a 360 degree angle like standard bulbs. The higher the colour temperature and the higher the lumens, the better colour rendition, creating better visibility of objects in the light field.
What colours are available in LED's?
The LED's are available in a number of different colours. Warm white and cool white tend to be the most popular but there are blue, yellow, green, red and RGB. Other colours are available but are usually special order.
Do they work with dimmers?
LED bulbs work with dimmers on full light output but the actual LED bulb does not have a dimming function.
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