Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!sdd.hp.com!uakari.primate.wisc.edu!samsung!uunet!motcid!koch
From: koch@motcid.UUCP (Clifton Koch)
Newsgroups: sci.electronics
Subject: Re: Blue LED
Message-ID: <5066@navy22.UUCP>
Date: 6 Nov 90 15:29:25 GMT
References: <9096@ncar.ucar.edu>
Organization: Motorola Inc., Cellular Infrastructure Div., Arlington Heights, IL
Lines: 19

From article <9096@ncar.ucar.edu>, by cook@stout.atd.ucar.edu (Forrest Cook):
-> Well, for a worst case scenario:  how about a decent resolution LED
-> screen of 1024 X 1024 and 3 LEDs per pixel at 20ma per LED:
-> 1024 X 1024 X .02 X 3 = 63000 AMPS! (approximately)
-> Multiply that by approximately 2 volts per LED and you get 126KW.
-> That's for an all white screen, of course.
-> Color balance would be a nightmare too.
-> Of course, someone could just have a row of 1024 LEDs and a spinning
-> mirror and cut that down to a reasonable 120 Watts, but I don't know how
-> easy the optics would be or how bright the display would be.
-> 

  Anyone who would run all the LEDs at once must own a power station :->

  In real life LED applications, they're always multiplexed, even in el
cheapo digital clocks.  For a NTSC TV, the resolution would only have to
be about 480 x 330.  Only 1 horizontal scan line would likely be on at any
given time, so the power drops to 330 x .02 x 3, or just under 20 watts.  A
wee bit more reasonable.