Light-Emitting Diode (LED) Key Terms

Light up your life with light-emitting diode (LED) key terms

By Kathryn Keep

Light-emitting diode (LED) technology has made everything from traffic lights to flashlights more efficient. Because they burn longer using less energy, they are the environmentally friendly choice. Florescent retrofits offer the chance for consumers to switch easily to LED. Emerging technology in solid-state lighting such as organic light-emitting diodes is changing many lighting applications. LED lighting can go where traditional lighting cannot, because it's smaller and requires far less power to operate.

LED

Light-emitting diodes are small, energy-efficient semiconductors that emit narrow-spectrum light. Their color depends on the chemical used into the bulb. LEDs give off very little heat compared with fluorescent or halogen bulbs, making them safer.
Try: EDInformatics.com offers a look into the design and applications of light-emitting diodes.

Solid-state lighting

Solid-state lighting refers to lighting designs using LED, organic LED or light-emitting polymers rather than incandescent lights that use filaments or gases contained in glass bulbs. This technology promises to become the new standard in lighting, because it saves energy and allows lighting flexibility.
Try: Read more about the many benefits of solid-state lighting at Rensselaer Polytechnic Institute at the Rensselaer Polytechnic Institute.

OLED

OLEDs, or organic light-emitting diodes, are solid-state lights that use thin films of organic molecules. Small screen devices, like cameras and PDAs, already use OLEDs, but they may soon be common in larger electronics, such as high definition televisions.
Try: Learn how OLED works and see its future promise at HowStuffWorks.

Color Rendering Index

Color Rendering Index, or CRI, refers to how well light sources render colors. There is much question as to the accuracy of using the CRI with LEDs and how best to measure color perception.
Try: The solid-state lighting page sponsored by the U.S. Department of Energy offers information and recommendations for using CRI with LED lighting.

Fluorescent retrofits

Florescent retrofits are LEDs made to replace florescent bulbs. They are safer and more energy-efficient without the glare and color distortion of florescent lighting.
Try: Check out Light Emitting Designs for more information on the benefits of florescent retrofits.

Polarity

LEDs have polarity, meaning they use both positive and negative terminals. Always consult a diagram when hooking up an LED. If you reverse the LEDs polarity, it cannot light. At higher voltages, reversing the polarity can damage the LED.
Try: Check out The Wolfstone Group for more information on determining LED polarity.