ABSTRACT
The light-emitting diode (LED) has found a multitude of roles as the field of optoelectronics has bloomed.
Infrared devices are used in conjunction with spectrally matched phototransistors in optoisolation couplers;
hand-held remote controllers; interruptive, reflective and fiber-optic sensing techniques; and low-cost IR
sources for fiber optic communications. Visible spectrum applications include simple status indicators and
dynamic power level bar graphs on a stereo or tape deck. This section will concentrate on digital display
applications of visible output devices.
