Hal Murray <[EMAIL PROTECTED]> 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? > > I remember getting a rack of memory for a PDP-10 that used LEDs because the > normal lights burned out all the time. That was back in the early 80s when > real computers had lots of lights. I think LEDs were pretty new then. (at > least new to me) > > The best reliability story I heard (many years ago) was about installing > another trans-Atlantic telephone cable. They used tubes long after > transistors were out. They knew how long the tubes would last. They didn't > have much data on transistors yet.
LED's from the 70's are not particularly reliable today. Like transistors, the problem was the packaging. Get a poor seal or some contaniments, and the lifetime was years, not decades. Now, there are some 70's era LED's in metal TO-style cans with epoxy windows. Those tend to be more reliable. It was in the 70's that they worked out the last kinks in plastic packaging. There are still a few aerospace applications where they still insist on metal applications for all semiconductors but really most modern plastic packages are more than good enough for most all applications. Tim. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
