This is a very standard LED. The lens is 3mm in diameter, and is diffused.
1.8-2.2VDC forward drop
Max current: 20mA
Suggested using current: 16-18mA
Luminous Intensity: 150-200mcd
Tech Tin Files: How LEDs work
The LED consists of a chip of semiconducting material doped with impurities to create a p-n junction. As in other
diodes, current flows easily from the p-side, or anode, to the n-side, or cathode, but not in the reverse direction.
Charge-carriers - electrons and holes - flow into the junction from electrodes with different
voltages. When an electron meets a hole, it falls into a lower energy level and releases energy
in the form of a photon.
The wavelength of the light emitted, and thus its color, depends on the band gap energy of the materials forming
the p-n junction. In silicon or germanium diodes, the electrons and holes usually recombine by a non-radiative
transition, which produces no optical emission, because these are indirect band gap materials. The materials
used for the LED have a direct band gap with energies corresponding to near-infrared, visible, or near-ultraviolet
LED development began with infrared and red devices made with gallium arsenide. Advances in materials science
have enabled making devices with ever-shorter wavelengths, emitting light in a variety of colors.
LEDs are usually built on an n-type substrate, with an electrode attached to the p-type layer deposited on its surface.
P-type substrates, while less common, occur as well. Many commercial LEDs, especially GaN/InGaN, also use
Most materials used for LED production have very high refractive indices. This means that much light will be
reflected back into the material at the material/air surface interface.
Thus, light extraction in LEDs is an important aspect of LED production, subject to much
research and development.