Erik Christiansen wrote:
.........snip.
Would the converse hold true ie. doubling for each 10°C fall bellow the temperature at which the lifetime is predicted? Yes, if the equipment is rated to operate at those temperatures. The examples I gave are simply based on Arrhenius' law, which has long served for describing the failure rate of electronics, in addition to its use in chemistry. It's only an approximation, as mentioned here:
http://www.osti.gov/bridge/purl.cover.jsp?purl=/841248-BSrmuy/webviewable/84... Many thanks I'll check out the URL; I seem to have a fascination with durability. There was an interesting program on the deserted city of Chernabyl on SBS; it made the point that little in the modern world will last more than a 100 years. Also amongst those materials which do last : stone obviously; there seem to be others which are peculiarly durable for no obvious reason; I seem to recall mention of Chinese cement containing rice powder !
The last time ...........snip
and
"Running at 80°C above nominal for 6 months is equivalent to 128 years of life.)" would imply the test was conducted at 0°C; is this standard or just for example? OK, with only commercial or industrial grade devices in the equipment, 80°C above nominal would be out of spec, since nominal is usually 25°C. It was just an example,
thanks
regards Rohan Mcleod