LED Lighting Benefits
What does LED stand for?
LED stands for “Light Emitting Diode”. Light Emitting Diodes, as the name states - are diodes. A diode is a semi-conductor device that permits current flow in one direction. Semiconductor diodes are a junction of two materials. One material has a surplus of positive charge (holes), and the other a surplus of negative charge (electrons). When one applies a forward voltage, the electrons and holes are brought together. They combine and release light energy - the 'light emitting' part of the name.
Is the LED a bulb?
LEDs do appear to be bulbs, but in fact, are not. LEDs are tiny semiconductors encapsulated in plastic which protects their components and helps to focus the light
What is the difference between an incandescent bulb and LED?
Incandescent creates light by the use of a filament. When power is applied, the filament glows and generates heat - which in turn produces light. LEDs are just the opposite. LEDs create light through a 'cold process'. When power is applied to semiconductors (usually gallium, arsenic and phosphorous), they're stimulated by the movement of electrons, these creating photons. Photons are the light that is visibly seen by humans.
How long do LEDs last?
LEDs are rated by manufacturers to operate under normal conditions for approximately 10 years or 50,000 hours of continuous use. As LEDs get older, they tend to dim and fade but aren't susceptible to blinking like incandescent or fluorescents.
LED Drivers and Adaptors
What are adaptors (or converter) used for?
Adaptors are also called converters or power adapters. For low voltage LED lights (12V, 24V) you would use an adaptor. It transforms your high voltage main (120V, 240V, etc) to the low voltage at which your LED can operate.
Driver - what is it and what type should I use with my LED?
A LED driver is the circuitry (a self-contained supply of power) that powers your light source with the needed drive current. But this current is still quite lumpy so we need to finetune the output that reaches the LED. For this to be accomplished we also need a resistor built in the driver circuitry. Drivers should be current regulated, so they deliver a consistent current over a range of load voltages
Can I use a dimmer with my LED?
Yes and No. If the LED product has a dimmable driver, it will work with a dimmer. It could be a 0-10V low voltage dimmer or a Triac dimmer, depending on the type of driver. If it doesn't have a dimmable driver, then it will not work with a dimmer.
LED Light Operation
If I know the exact voltage across my LED can I determine the exact current?
No you can't unfortunately, not exactly. If you know the voltage across the LED that doesn't mean you know the exact current flowing thru your LED at that time. LEDs are funny things. They have high mobility inside the semiconductor crystal emitting the light. This means they are quite unpredictable as to finding out the exact resistance at a certain voltage - therefore the exact current flowing thru your LED. All you can do is spot checks in various discrete stages. At this stage we do not have a formula. Once we'll have one, it'll still likely to be too complex to be used by an average do-it-yourselfer.
LED meltdown - what is it and how it "works"?
The thermal runaway effect ultimately killing your LED is popularly called LED meltdown. The current through the junction will tend to increase as the temperature rises. This in turn will heat you junction further. Beyond a certain maximum point this can not be reversed. Your LED will melt down and die.
Maximum operating point - what is it?
You may get a maximum operating point either as current or voltage. For example, when you read that your LED is "3 Volt" you are actually given a maximum operating point expressed in voltage. What it means is that your 3V LED usually operates below that voltage and has a maximum limit of 3V.
Can LEDs be damaged if hooked up backwards?
Yes, they can. LEDs are diodes and only allow power to pass in one direction. To ensure that you will get the most life out of our LED devices, we add additional circuits to prevent this from occurring in both AC and DC applications..
Are LEDs affected by extreme conditions?
LEDs are geared for harsh environments. LEDs function from -40F to 180F. There is no delay or required "warm up time" for LEDs to function.
Do LEDs attract insects?
No they do not. Insects see entirely different spectrums of light and are attracted to ultraviolet light. A side note - flowers create "nectar guides", invisible to the human eye and ultraviolet light attracts insects to flowers for reproductive purposes. This is not to say that all bugs aren't attracted to LED lights, but most can't see the light that LEDs produce.
Are LED's inherently directional?
No. One way to boost the luminous intensity spec (usually given in candelas of millicandelas) is to focus the beam more tightly. The same light flux, focused into a tighter beam, will give a higher luminous intensity spec. So indicator LEDs with 10 degree beam width are popular in part because they have higher specs compared to the same LED packaged to have a 30 or 70 degree beam width. It's more common to see illumination-grade LEDs rated in lumens, which doesn't take into account the focusing of the beam. Arrays built from narrowly focused LEDs will be narrowly focused; arrays built from other beam distributions will exhibit the beam distribution of their component LEDs. Narrow-beam LEDs and arrays can lose apparent impact when viewed slightly off-axis.