Definition: LED bulb

A light source 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, and they can last from 10 to 20 years.

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.

Here to Stay
For a long time, LED bulbs were much more expensive than incandescents; however, today, they are much cheaper and are the primary household bulb technology as incandescent bulbs, at least the common lamp variety, were banned in the U.S. in 2023.

There Are Some Issues
In general, LED bulbs are very reliable and deliver excellent light, but people can encounter a buzz or flicker when they are used with old dimmer switches. In addition, LED bulbs emit various shades of white, and buyers must read the packaging information (see color temperature). See incandescent bulb, halogen bulb, fluorescent bulb, Acandescent bulb, OLED lighting and LED.

Incandescent vs. LED

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).

All Shapes and Colors

This Philips LED bulb hardly resembles the incandescent bulb, which has been used for more than a century.

LED Night Light - 23 Times Less Power

Instead of a 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.

It's Not What You Think

The 16 LEDs are totally hidden inside a shell that looks exactly like an incandescent bulb.