How to Select Light Emitting Diodes (LEDs)                          Image Credit: Digi-Key Corporation, Kingbright Corporation, Newark What are LEDs? Light emitting diodes (LEDs) are PN junction devices that give off light radiation through electroluminescence when forward biased. They are used as various indicators in aviation, automotive and traffic lighting, as well as lighting for some...
Learn More about Light Emitting Diodes (LED)


Q & A on Light Emitting Diodes (LED)

We asked our users for their input on Light Emitting Diodes (LED). Here are the results of 901 users familiar with Light Emitting Diodes (LED).

Who Took Our Poll? | Design Trends | Applications and Use | Features | Buying Advice

Who Took Our Poll?Top

Design TrendsTop

Q:
What new technologies are influencing LED design?
132 answers
Answers:
Nano technology have made an outstanding contribution to color variation. Led's in the area of entertainment have made great progress, especially in the area of energy efficient televisions. The Chinese have made outstanding contributions to exterior lighting with high power, high lumen output LED's. American companies have made great strides in flashlight technology and for horticulture. And as we all know, if it were not for the Japanese we would probably still not have blue/white LED's. However, I have to credit the UK with perfecting the on-board multi-chip packing technique for high power/lumen output for interior lighting.
~Shawn W, Research & Development, Los Angeles, CA
I remember having studied about two things in the recent developments of LEDs. The first one is the increasing intensity of the light emitted per watt. Bright LEDs are evolving rapidly, which may largely transform the future of lighting. The second is the advent of VLSI and silicon chip technologies that are helping evolve LEDs in power consumption and size, besides other intrinsic advantages of the chip industry.
~Shanmugasivam P, Faculty/Staff, Mumbai, India
Phosphor conversion technology is a unique way of creating coloured LEDs the same way as manufacturers create white LEDs. This influences the design by providing higher output colour LEDs that are different from typical standard coloured LEDs.
~Steven S, Optical Engineer, Niagara Falls, Canada
See More Answers
Q:
From your perspective, which companies are creating the most innovative LED?
116 answers
Answers:
Hamamatsu, Siemens and others - too many to list.
~Engineering, Faculty/Staff/Student, ISTANBUL, Turkey
Cree has a nice line of dimmable 120 VAC LED's. Fix the form factor so these become screw-in halogen replacements and they will sell like crazy.
~Richard S, Home builder and amateur energy efficiency designer, Brookline, MA
Avago® Technologies for my applications work the best.
~JT W, Research & Development, Sunland, 91040
See More Answers

Applications and UseTop

Q:
What are some of the applications you have used LED for?
234 answers
Answers:
The application that comes first to our mind as soon as we think of LED is indication. LED acts as a great indicator of data and power having entered in our electronic system. There could be no electronic device or system in the world that could exist without a power indication LED. Similarly in lost digital circuits, especially the wireless ones, always have LEDs on their path showing successful data transmission and reception. The second application of this wonderful light is as LED matrix indicators. I have often used an LED indicator or the seven segment displays in many section which does not require a complex LCD display. The latest use of LED has been for illumination. Because of its pluses like, low cost, low power and durability, LEDs are largely taking over in the field of illumination like torch-lights, Signals, etc. and so even I tried using LED for solar powered street light project which was successful. One more application that I tried was using LEDs for decorative lighting wherein we tried to make a pattern of group's logo using LEDs. I have even used LEDs, especially the bright red and IR ones, for sensors and in fact, this application has been largely dominant in many of my automation related projects. Although I end up with this, there are in fact a lot more of it.
~Shanmugasivam P, Faculty/Staff, Mumbai, India
Some of the more interesting applications that I have used Light Emitting Diode (LED) for are Targeting systems. IED training Devices. Weapons Systems, Low voltage electronics prototype manufacturing. Infrared Systems. Electronic Strobe Flares. Underwater Demolition Marker's.
~JT W, Research & Development, Sunland, 91040
I have used LED's in flashlights, general interior lighting and for a perpetual energy project that I have been working on for three years now. I had an in-depth conversation with thee physicists concerning this and have made a few believers. I understand the different types of LED's that exist, how they function, and their general uses.
~Shawn W, Research & Development, Los Angeles, CA
See More Answers
Q:
Please share with us any “non-standard” applications that LED have been used for.
79 answers
Answers:
My "sideline" hobby/business is creating new pieces of furniture from old metal cabinets or simply restoring & refurb of mid-century modern, high end furniture. In creating my metal cabinets, I build in LED lighting on the back or underside of each piece so that it's more than just furniture - it provides ambient lighting in the room.
~Wes B, Creative Director, Photographer, Designer, Albany, NY
Helped spec parts for a lighted guitar for a "final four" half time show.
~Don B, Technical Support, Arlington, TX
I am the first artist using led inside an artwork using batteries.
~Luciano M., Artist, Milan, Italy
See More Answers
Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of LED?
47 answers
Answers:
Green Bay Wisconsin converted traffic lights to LED and found that insufficient heat was generated to melt snow. So, every time a big snow storm came through in 2009, drivers could not see whether the lights were red or green. I think a modification has been added to correct this now, but don't know the details.
~James M, Engineer, Two Rivers, WY
A simple mistake of using a "RED" LED as a indicator light. Many of our customers and our own field support personnel initially thought the "RED" light indicated something was wrong. Lots of dollars wasted on problems that did not exist. Next time, choose green for a basic indicator LED color.
~Michael B, Technical Director in R&D, Austin, TX
Heat death...LED's have a general lifespan of ten years if ran continuously. However they tend to burn out quickly if you do not choose the proper cooling method or proper heat sink size. Also the wrong voltage will kill the LED's immediately, especially if you apply the wrong amount or too much voltage.
~Shawn W, Research & Development, Los Angeles, CA
See More Answers

FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
138 answers
Answers:
Combine an LED array built on top of an LED driver chip as one part. * The chip would provide dimming and all power regulation. * a big thermal pad underneath the chip for heat dissipation. * make this a 4 pin part. 2 pins for power input, 2 pins for control of dimming. This would make LED design KISS for everyone -
~Michael B, Technical Director in R&D, Austin, TX
Probably it would be to have an LED with an internal solar power source or maybe a small battery that could keep it ON all times. I am also looking for the reduction in the costs of high brightness LEDs. Further there may be LEDs with a knob to change the frequency of light emission.
~Shanmugasivam P, Faculty/Staff, Mumbai, India
Manufacturers' voluntary disclosure of data regarding Lumen Maintenance, Color Drift, and Correlated Color Temperature over expected life of product, and Compliance with IEC 62471-2 for photobiological safety. Ease of thermal management with newer technologies and materials.
~Mukesh P, Standards & Regulatory Affairs Manager, Boise, ID
See More Answers
Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of LED?
76 answers
Answers:
Beware the dreaded "heat sink". Over drive your LED and it will drive right over a cliff to failure. Good heat sink is vital.
~Anthony L, Engineering Consultant, Delray Beach, FL
Do not underestimate heat dissipation requirements. Target double what you need, and you will extend the life of your design.
~Michael B, Technical Director in R&D, Austin, TX
If you have high brightness applications, do make sure that the effect of temperature has on the color of the emission from the LED. Design from the needed Lumen/Candela/Candela Seconds and the CIE 1931 Color coordinates, backwards into what LED you should be using. Account for the transmissivity of all optical material.
~Mukesh P, Standards & Regulatory Affairs Manager, Boise, ID
See More Answers

Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using LED?
79 answers
Answers:
Multicolor LEDs are still hardly being used other than for decorative lightings. So I would suggest people to start using multi color LEDs for data and power indication in circuits. This could also help us in debugging circuits. Secondly, we often tend to use LEDs repetitively from one project to another. This may often leave the LED legs damaged or broken. In such a case, identifying the anode and cathode terminals by leg size could lead to an error. It is often a good idea to identify the pins by seeing the inside of the LED.
~Shanmugasivam P, Faculty/Staff, Mumbai, India
#1. In purchasing lighting for your home - be sure to replace incandescent bulbs with a "warm white". #2. consider purchasing RGB LED bulbs with a remote control for ambient lighting fixtures so you can alter the look of a room. #3. Start by replacing your incandescent household lighting with LED bulbs based on how often the light is used. Start with any lighting that stays on all the time or works on a timer. #4. While it's somewhat unconventional, warm white & white LED holiday string lights can be re-used behind furniture & under cabinets all year round to provide ambient light & avoids having to turn on the overhead incandescent bulbs when walking into a room.
~Wes B, Creative Director, Photographer, Designer, Albany, NY
If you want a good low power LED seek out Nichia. They are a little expensive but worth every penny. If you are into horticulture use LedEngin. If you are looking for interior or exterior lighting...the Chinese make the lowest cost, highest volume products available (their lumen output is sometimes inflated a little.). If you are into flashlights, Cree and Philips Lumileds are the companies with the best products. However LedEngin just made a power move on them both with its new line.
~Shawn W, Research & Development, Los Angeles, CA
See More Answers

Related eNewsletters
See More

Also on GlobalSpec...
  • Receive email updates on new products and suppliers of interest to you
  • Online, interactive conferences / trade shows featuring latest news and industry trends
  • CR4
    Q&A and discussion for the engineering, scientific, and technical community
  • Engineering and scientific news from hundreds of sources
  • Industrial manufacturers and distributors