|LED LAMP FAQs
What is an LED?
Are LEDs too expensive?
How does a diode produce light?
How is white light created in an LED lamp?
Why is an LED lamp better than an incandescent equivalent?
Why is an LED lamp better than a CFL lamp?
Why is it so important to have good heat management within your LED lamps?
Do LED lamps emit any UV or infrared radiations?
What is an LED driver?
What type of transformer can be used for LED lamps?
What is LM79 testing used for?
What is LM80 testing used for?
WHAT IS AN LED
Light emitting diodes (LED's), are small diodes that are comprised in LED lamps and fit easily into an electrical circuit. But, unlike incandescent bulbs, they do not have a filament that will burn out, and they do not get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and last just as long as a standard transistor.
A diode is the simplest sort of semiconductor device. A semiconductor is a material with varying ability to conduct electrical current. Most semiconductors are made of a poor conductor material that has had impurities (atoms of another material) added to it. The process of adding impurities is called doping.
In the case of LED lamps, the conductor material is typically aluminum-gallium-arsenide (AlGaAs). In pure aluminum-gallium-arsenide, all of the atoms bond perfectly to their neighbors, leaving no free electrons (negatively-charged particles) to conduct electric current. In doped material, additional atoms change the balance, either adding free electrons or creating holes where electrons can go. Either of these additions makes the material more conductive.
ARE LEDS TOO EXPENSIVE?
When simply evaluating the initial cost of an LED lamp versus a halogen equivalent lamp, it can often be seen that the initial LED lamp cost is higher than its traditional lamp equivalent. However, it is important to always keep in mind that lamp cost is but only a fraction of the total cost of ownership of a lamp.
In order to see the true lamp costs, it is important to remember to factor in energy costs, lamp replacement costs as well as the environmental impact. The savings amounting from these factors can add up quickly, especially when there are many lamps in question. LED lamps are continuously evolving and as they continue to change, so will the associated initial costs and savings.
HOW DOES A DIODE PRODUCE LIGHT?
A diode emits light as the electrons drop from a higher orbital to a lower one. Different materials will determine the size of the drop which in turn determines the color of light being produced.
The wavelength (in nanometers) of the light emitted = the COLOUR of the LED.
HOW IS WHITE LIGHT CREATED IN AN LED LAMP?
White light can be created in one of three ways.
The colour of an LED is determined by the semiconductor material, not by the colouring of the plastic covering.
- White light is created by using a blue GaN (gallium nitride) LED covered by a yellowish phosphor coating. A mix of blue and yellow light gives the appearance of white.
- Another way to produce white light from LEDs is by mixing red, blue, and green colours with a computer controlled mixer. The advantage of this method is that we can then adjust the intensities of each LED to exactly the right shade of white to be emitted.
- Thirdly, white light can be produced by using LEDs that produce UV light combined with tri-phosphor materials (similar to a fluorescent lamp).
WHY IS AN LED LAMP BETTER THAN AN INCANDESCENT EQUIVALENT?
LED lamps are the lighting of the future and with each passing year they are becoming increasingly efficient and still maintaining quality. Currently, LED lamps are more than 85% more efficient than incandescent lamps since they emit less heat and have extremely long lives. Most of the energy emitted from incandescent lamps is converted to heat instead of light, which significantly decreases their efficiency rate.
WHY IS AN LED LAMP BETTER THAN A CFL LAMP?
Although CFL lamps have made progress over the years, they still have the drawback of being damaging to the environment since they contain hazardous materials, such as mercury and therefore need to be properly disposed of.
LED lamps contain no mercury and emit no damaging UV rays. Further more, they are also 50% more efficient than CFL lamps, are instant-on lights and will dim without any flicker.
WHY IS IT SO IMPORTANT TO HAVE GOOD HEAT MANAGEMENT WITHIN YOUR LED LAMPS?
The heat management of an LED lamp is critical to its efficiency and longevity. When an LED produces light some of that electricity is actually turned into heat. The job of the heat sink is to move that heat away from the lamp in order to ensure the LED lamp does not run at a high temperature, which decreases efficiencies and life.
Without having an efficient heat management system and heat sinking in place, there can be many negative effects on the LED lamp’s characteristics, including the following:
- Decrease in forward voltage, which could strain other LED components causing them to increase their temperature.
- Optical wavelength can shift, which can consequently cause coloured LED lamps to appear different colours.
- Overall loss of efficiencies and light output
DO LED LAMPS EMIT ANY UV OR INFRARED RADIATIONS?
No, LED lamps provide cool light that is free from any harmful UV and infrared emissions. The lack of these emissions means that there is no discoloration of items under this light.
WHAT IS AN LED DRIVER?
Similar to how a ballast works with fluorescent and HID lamps, an LED driver supplies the power to the LED lamp It helps convert incoming main voltage (120V) AC power to the necessary low-voltage DC power required for LED lamps. The driver protects the lamp from line voltage fluctuations.
WHAT TYPE OF TRANSFORMER CAN BE USED FOR LED LAMPS?
Transformers are only needed for low voltage LED lamps. Typically LED lamps should be able to operate on both magnetic and electronic transformers. However, there are many LED products in the market that only operate on one type of transformer. It is important to verify this information prior to considering an LED lamp most suitable for your application. The transformer can also be built directly into the fixture.
WHAT IS LM79 TESTING USED FOR?
LM79 standard, published by the Illuminating Engineering Society of North America (IESNA), tests the photometerics of the lamp, including lumen output, color temperature, CRI, watts and lumen efficacy.
WHAT IS LM80 TESTING USED FOR?
LM80 standard, published by the Illuminating Engineering Society of North America (IESNA), lights up an LED array for 6 000 hours and based on those initial results, extrapolates that data to calculate a lifetime for the LED lamp. It is often used as the primary method for calculating lumen depreciation.