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What is an LED?What is an LED?
LED stands for Light Emitting Diode
This is how they work…
LED stands for Light Emitting Diode
This is how they work…
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How Diodes workHow Diodes work
A diode allows an electric current to flow in one direction, but blocks it in the opposite direction, much like an electronic version of a check valve.
A diode allows an electric current to flow in one direction, but blocks it in the opposite direction, much like an electronic version of a check valve.
How Light Emitting Diodes work
How Light Emitting Diodes work
A Light Emitting Diode emits light when an electric current passes through it.
Basically, LED's are tiny light sources that fit easily into an electrical circuit.
A Light Emitting Diode emits light when an electric current passes through it.
Basically, LED's are tiny light sources that fit easily into an electrical circuit.
Why get light from LEDs?Why get light from LEDs?
They are illuminated solely by the movement of electrons in a very small piece of semiconductor material inside them referred to in the “LED world” as a die.
They don't have a filament to burn out, and they don't get especially hot.
They are illuminated solely by the movement of electrons in a very small piece of semiconductor material inside them referred to in the “LED world” as a die.
They don't have a filament to burn out, and they don't get especially hot.
How are LEDs made?How are LEDs made?
These dies, the main component in LEDs, are processed in wafer form similar to silicon-integrated circuits, and broken out into individual dice or chips.
These dies, the main component in LEDs, are processed in wafer form similar to silicon-integrated circuits, and broken out into individual dice or chips.
Chip size for visible signal LEDs generally fall in the Chip size for visible signal LEDs generally fall in the range of 0.18mm square to 0.36mm square (smaller range of 0.18mm square to 0.36mm square (smaller than a pin head). High power LEDs for lighting are than a pin head). High power LEDs for lighting are yet larger.yet larger.
Internals of a Blue LEDInternals of a Blue LEDWhite visible light starts with
a die that emits blue light (It’s coated with Indium gallium nitride, causing the blue coloring)
The basic LED structure consists of the die, a lead frame where the die is actually placed, and the encapsulation epoxy, which surrounds and protects the die and disperses the light (see left).
White visible light starts with a die that emits blue light (It’s coated with Indium gallium nitride, causing the blue coloring)
The basic LED structure consists of the die, a lead frame where the die is actually placed, and the encapsulation epoxy, which surrounds and protects the die and disperses the light (see left).
What about a White LED?What about a White LED?
To create White light, a coating of phosphor is placed on the die.
The recess in the anvil is
shaped to project the radiated light forward.
The die's top contact is
wire bonded to the other lead frame terminal, the post, to complete the circuit.
To create White light, a coating of phosphor is placed on the die.
The recess in the anvil is
shaped to project the radiated light forward.
The die's top contact is
wire bonded to the other lead frame terminal, the post, to complete the circuit.
So, how do you get white light?
So, how do you get white light?
As current flows, the die would normally produce blue light. But in this case another color is emitted as determined by the precise amount of phosphor applied to the die. That phosphor fluoresces to achieve a near-white light
That white light is sorted to colors like warm white, white and cool white and assembled in quantities in tubes.
As current flows, the die would normally produce blue light. But in this case another color is emitted as determined by the precise amount of phosphor applied to the die. That phosphor fluoresces to achieve a near-white light
That white light is sorted to colors like warm white, white and cool white and assembled in quantities in tubes.
These LEDs are mounted on printed circuit boards in shatter-resistant
Polycarbonate tubes…
These LEDs are mounted on printed circuit boards in shatter-resistant
Polycarbonate tubes…
……with proper with proper electrical electrical contacts they contacts they are designed are designed to replace to replace fluorescent fluorescent lamps!lamps!
How long do LEDs last?How long do LEDs last?LEDs have a mean time between failures
usually in the range of 100,000 to over 1,000,000 hours. But, this is a long time for continuous operation, considering that a year is 8784 hours at most. *
Temper this with application, added circuitry and housing. In practice, the useful measure of LED lifetime is its half-life. When the light output falls off to half the original, an LED is deemed to have reached the end of its life
* Based on life decay model, 67-21 series lifetime can reach L70@ 25297 hr and L50@ 47466 hr under test condition of 20mA, 25 C and 60%RH.
LEDs have a mean time between failures usually in the range of 100,000 to over 1,000,000 hours. But, this is a long time for continuous operation, considering that a year is 8784 hours at most. *
Temper this with application, added circuitry and housing. In practice, the useful measure of LED lifetime is its half-life. When the light output falls off to half the original, an LED is deemed to have reached the end of its life
* Based on life decay model, 67-21 series lifetime can reach L70@ 25297 hr and L50@ 47466 hr under test condition of 20mA, 25 C and 60%RH.
How do fluorescent tubes work?
How do fluorescent tubes work?
Electricity flowing from electrode to electrode in fluorescent lamps produce a charge causing electrons to travel through the argon gas-filled tube. This energy vaporizes liquid mercury inside the tube which in turn releases ultraviolet (UV) photons.
Electricity flowing from electrode to electrode in fluorescent lamps produce a charge causing electrons to travel through the argon gas-filled tube. This energy vaporizes liquid mercury inside the tube which in turn releases ultraviolet (UV) photons.
The ultraviolet light is transformed into visible light by the The ultraviolet light is transformed into visible light by the phosphors on the inside of the tube. In doing so, about 80% phosphors on the inside of the tube. In doing so, about 80% of the energy used is released as heat not light and, inof the energy used is released as heat not light and, in a warm climate, that increases your air conditioning costs.
Lamp lifetimes comparedLamp lifetimes compared
0
5
10
15
20
25
30
35
40
45
50
LifeExpectancy
T12
T8
LED
0
5
10
15
20
25
30
35
40
45
50
LifeExpectancy
T12
T8
LED
Hours x 1000 Hours x 1000
Some facts about fluorescent tubesSome facts about fluorescent tubes
Require inefficient, expensive ballasts Generate higher utility bills Significantly shorter life than LEDs Poor performance in cold environments Require immediate replacement, or
have wasted life from group relamping When broken, you have glass shards
contaminated with mercury Can sound noisy and flicker as they age Dimming is too expensive to be practical
Require inefficient, expensive ballasts Generate higher utility bills Significantly shorter life than LEDs Poor performance in cold environments Require immediate replacement, or
have wasted life from group relamping When broken, you have glass shards
contaminated with mercury Can sound noisy and flicker as they age Dimming is too expensive to be practical
Benefits of LED LitesBenefits of LED Lites
Long life (50,000 hrs).60% savings in your
lighting energy bill.No humming/no buzzing.Do not generate significant heat.Not affected by vibration.No toxic components, no disposal costs.Do not attract insects.Efficient in cold temperatures.
Long life (50,000 hrs).60% savings in your
lighting energy bill.No humming/no buzzing.Do not generate significant heat.Not affected by vibration.No toxic components, no disposal costs.Do not attract insects.Efficient in cold temperatures.
What savings can I expect?What savings can I expect? A building operating 12 hours a day can usually
pay back the cost of the lamps in electrical savings within 24 months. The balance of the life of the lamps (7-8 years) can show savings of 60% or more over previous expenditures. Dollar amounts are dependent on the number of fixtures and local power rates.
A savings calculator is available. Merely plug in figures found in a lighting survey of your building.
www.ACT-SOLUTIONS.COM
A building operating 12 hours a day can usually pay back the cost of the lamps in electrical savings within 24 months. The balance of the life of the lamps (7-8 years) can show savings of 60% or more over previous expenditures. Dollar amounts are dependent on the number of fixtures and local power rates.
A savings calculator is available. Merely plug in figures found in a lighting survey of your building.
www.ACT-SOLUTIONS.COM
How about even more savings?
How about even more savings?
Dimming LED Lites (controlLED Lites) provide even more savings.
controlLED Lites can operate from a variety of control signals.
They can controlled by occupancy or light level sensors and be connected to existing building automation systems.
www.ACT-SOLUTIONS.COM
Dimming LED Lites (controlLED Lites) provide even more savings.
controlLED Lites can operate from a variety of control signals.
They can controlled by occupancy or light level sensors and be connected to existing building automation systems.
www.ACT-SOLUTIONS.COM
