Btw, in a stastics class I learned that light bulbs don't fail because of filament failure at switch-on. The failure rate is constant with time (I forget which distribution models this, but whichever is a "memoryless" distribution) which indicates that the cause for failure is most likely external, i.e. power surges on the line.
Alvin Auerbach <[EMAIL PROTECTED]> wrote: Electronic reliability is a tricky business. With tubes, yes, filaments had a well known "wear-out mechanism" that reduced life with time on. Surges at turn-on could also reduce life. Then again, it depends on individual design, too. Some designs ran the filaments at well below rated voltage, greatly increasing their life. Some designs had the power come on slowly, reducing power surges. Solid state stuff doesn't have a wear-out mechanism, AFAIK. However there are individual possibilities. Some power supplies might have an overvoltage at turn-on, thus stressing the parts that it is powering. On the other hand, no electronic part has a perfect seal. Heating the part by using it and then cooling the part by not using it may cause slight "breathing" and some moisture may make it through the seal, eventually causing corrosion and failure. With good solid state component design, good over all circuit design, and good cooling design, today's electronic gadgets may have such a long life, that it's a coin toss as to what finally does it in. Then again, who says that everything has good design? What with pressures to cut costs, and pressures to quit designing and refining and get the gadget shipped, good design may be an unattainable goal. >This has never been shown. There's no question a cold filament (eg in >a light bulb or even a vacuum tube) experiences an initial surge, and >thus a higher failure rate at power-on. But modern electronics don't >experience that. > >Now, from a human perspective, it may *seem* to be true. "I've had >enough with this computer; I'm going to bed". The next morning, it >won't boot. While it may seem like a power-on failure, it isn't. > >>However, the most stressful moment for electronics is the initial >>power cycle (i. e., "turning it on"). > > ************************************************************************ * ==> QUICK LIST-COMMAND REFERENCE - Put the following commands in <== * ==> the body of an email & send 'em to: [EMAIL PROTECTED] <== * Join the list: SUBSCRIBE COMPUTERGUYS-L Your Name * Too much mail? Try Daily Digests command: SET COMPUTERGUYS-L DIGEST * Tired of the List? Unsubscribe command: SIGNOFF COMPUTERGUYS-L * New address? From OLD address send: CHANGE COMPUTERGUYS-L YourNewAddress * Need more help? Send mail to: [EMAIL PROTECTED] ************************************************************************ * List archive at www.mail-archive.com/[email protected]/ * RSS at www.mail-archive.com/[email protected]/maillist.xml * Messages bearing the header "X-No-Archive: yes" will not be archived ************************************************************************ ************************************************************************ * ==> QUICK LIST-COMMAND REFERENCE - Put the following commands in <== * ==> the body of an email & send 'em to: [EMAIL PROTECTED] <== * Join the list: SUBSCRIBE COMPUTERGUYS-L Your Name * Too much mail? Try Daily Digests command: SET COMPUTERGUYS-L DIGEST * Tired of the List? Unsubscribe command: SIGNOFF COMPUTERGUYS-L * New address? From OLD address send: CHANGE COMPUTERGUYS-L YourNewAddress * Need more help? Send mail to: [EMAIL PROTECTED] ************************************************************************ * List archive at www.mail-archive.com/[email protected]/ * RSS at www.mail-archive.com/[email protected]/maillist.xml * Messages bearing the header "X-No-Archive: yes" will not be archived ************************************************************************
