LED
Jack Zou
www.diecastingpartsupplier.com
2015-01-20 18:15:55
A light-emitting diode (LED) is a two-lead semiconductor light source. It is a pn-
junction diode, which emits light when activated.When a suitable voltage is applied to
the leads, electrons are able to recombine with electron holes within the device,
releasing energy in the form of photons. This effect is called electroluminescence, and
the color of the light (corresponding to the energy of the photon) is determined by the
energy band gap of the semiconductor.
An LED is often small in area (less than 1 mm2) and integrated optical components may be
used to shape its radiation pattern.
Appearing as practical electronic components in 1962,the earliest LEDs emitted low-
intensity infrared light. Infrared LEDs are still frequently used as transmitting
elements in remote-control circuits, such as those in remote controls for a wide variety
of consumer electronics. The first visible-light LEDs were also of low intensity, and
limited to red. Modern LEDs are available across the visible, ultraviolet, and infrared
wavelengths, with very high brightness.
junction diode, which emits light when activated.When a suitable voltage is applied to
the leads, electrons are able to recombine with electron holes within the device,
releasing energy in the form of photons. This effect is called electroluminescence, and
the color of the light (corresponding to the energy of the photon) is determined by the
energy band gap of the semiconductor.
An LED is often small in area (less than 1 mm2) and integrated optical components may be
used to shape its radiation pattern.
Appearing as practical electronic components in 1962,the earliest LEDs emitted low-
intensity infrared light. Infrared LEDs are still frequently used as transmitting
elements in remote-control circuits, such as those in remote controls for a wide variety
of consumer electronics. The first visible-light LEDs were also of low intensity, and
limited to red. Modern LEDs are available across the visible, ultraviolet, and infrared
wavelengths, with very high brightness.