A light source that is created by a light emitting diode (LED). For decades, LEDs have been used as indicator lights on myriad products; however, starting in the 2000s, they began to replace incandescent, halogen and CFL fluorescent bulbs. LEDs draw considerably less power and are up to 80% more efficient. Although claims are made for some bulbs lasting 25 years, one should expect a long lifespan under normal usage.
As of 2020, LED bulbs are still more expensive than incandescent bulbs; however, prices are constantly decreasing. Companies continue to experiment with numerous designs. For example, when red, green and blue LEDs are combined, they produce white light. Another method uses a blue LED and yellow or red phosphors.
There Are Issues
In general, most LED bulbs are reliable and deliver excellent light, but users encounter more problems than with previous bulb technologies. LEDs emit various shades of white, and buyers must read the packaging information (see color temperature
). In addition, all dimmer switches must be LED compatible, and sometimes even those do not match up with the bulbs, causing a buzz or flicker. See incandescent bulb
, halogen bulb
, fluorescent bulb
, Acandescent bulb
, OLED lighting
Incandescent vs. LED
All Shapes and Colors
The LED bulb on the right draws 3.5 watts but delivers the same brightness as the 45-watt bulb on the left. This LED bulb casts a very white light; however, LED bulbs run the gamut from warm yellow to white-blue (see color temperature
This Philips LED bulb hardly resembles incandescent lighting, which has been used for more than a century.
LED Night Light - 23 Times Less Power
Instead of the 7 watt incandescent bulb in the typical night light, this LED uses 0.3 watts. The blue arrow points to the single LED; the red arrow shows the light sensor.
Way More Complex
The LED bulb (top left) is a replacement for the 78mm T3 halogen bulb (bottom right). Instead of a simple filament, the LED bulb contains 75 LEDs along with electronic components inside.
The 16 LEDs are totally hidden inside a shell that looks exactly like an incandescent bulb.