In 1957, Braunstein further demonstrated that the rudimentary devices could be used for non-radio communication across a short distance. As noted by Kroemer Braunstein".. had set up a simple optical communications link: Music emerging from a record player was used via suitable electronics to modulate the forward current of a GaAs diode. The emitted light was detected by a PbS diode some distance away. This signal was fed into an audio amplifier, and played back by a loudspeaker. Intercepting the beam stopped the music. We had a great deal of fun playing with this setup." This setup presaged the use of LEDs for optical communication applications. COUNT 5
QSN1 What year was it discovered that early LED instruments could be used for non-radio communication? ANS1 1957 QSN2 Who discovered non-radio uses for early LED devices? ANS2 Kroemer Braunstein QSN3 The current in non-radio communication had to go through what type of component? ANS3 a GaAs diode QSN4 What other component was needed to detect the first current of a non-radio signal? ANS4 a PbS diode QSN5 What final device was needed to hear the signal from the initial GaAs diode? ANS5 audio amplifier