LED Bulbs are a source for electric light for use in light fixtures that produces light using light-emitting diode (LED). They have a lifespan many times longer than equivalent incandescent lamps, and are significantly more efficient than most fluorescent lamps. They also use only about 10% of the energy an incandescent lamp requires.
Similar to incandescent lamps (and unlike most fluorescent lamps), LED bulbs come to full brightness immediately with no warm-up delay. Frequent switching on and off does not reduce life expectancy as with fluorescent lighting though light output decreases gradually over the lifetime of the LED.
Some LED Bulbs are made to be a directly compatible drop-in replacement for incandescent or fluorescent lamps. LED Bulbs packaging may show the lumen output, power consumption in watts and description of the color it lights ie. warm white, cool white or colored, operating temperature range, and sometimes the equivalent wattage of an incandescent lamp of similar luminous output.
The directional emission characteristics of LEDs affect the design of LED Bulbs. While a single power LED may produce as much light output as an incandescent lamp using several times as much power, in most general lighting applications multiple LEDs are used. This can form a lamp with improved cost, light distribution, heat dissipation and possibly also color-rendering characteristics.