On Apr 30, 2008, at 18:56, Hal Murray wrote: >> LEDs been viable since at least the early 70's? Talk about planned >> obsolescence... > > How reliable were the early LEDs? When did they start to get used > in high > reliability applications? When I joined Hewlett-Packard in 1970, they made their first red leds and claimed 50000 hours mtbf. Henk