The light from LEDs can be modulated very quickly so they are used extensively in optical fiber and free space optics communications. This includes remote controls, such as for TVs, VCRs, and LED Computers, where infrared LEDs are often used. Opto-isolators use an LED combined with a photodiode or phototransistor to provide a signal path with electrical isolation between two circuits. This is especially useful in medical equipment where the signals from a low-voltage sensor circuit (usually battery-powered) in contact with a living organism must be electrically isolated from any possible electrical failure in a recording or monitoring device operating at potentially dangerous voltages. An optoisolator also allows information to be transferred between circuits not sharing a common ground potential. COUNT 5
QSN1 Where are LEDs often used? ANS1 free space optics communications QSN2 Where are opto-isolators found? ANS2 medical equipment QSN3 What is an example of a device that uses free space optic communications? ANS3 remote controls QSN4 What does an optoisolator do? ANS4 allows information to be transferred between circuits not sharing a common ground potential QSN5 In what common household item can you find infrared LEDs? ANS5 LED Computers