At 10:45 PM 02/07/98 -0500, you wrote:
>Wow! I never expected that the manufacturing process for each individual
>chip involved so much testing! Is this, then, a major or maybe THE major
>share of the price of the IC? It would seem to me to be a fairly expensive
>undertaking. Also, in a typical consumer electronic device (take a
>microwave oven, TV, or clock, for example), is the initial failure rate
>less than 99.99% ??! Again, this is news to me. As a first year EE student
>and an avid electronics hobbyist, I have never had any of my designs go
>into production, but have considered trying several times. I guess that
>this is the reason why I am unfamiliar with the expectations of
>manufactured devices. It just seems that in my experience, I have seen at
>least several of the applicances which I have purchased fail prematurely or
>never work. If the rate were really 99.99%, I must be very unlucky. Then
>again, we engineers are especially cursed by murphy, right :)
>
>Sean
>
Sean;
Don't forget that if you have ten parts, each with a reliability of 0.999,
then the system has a reliability of 0.99 to the fifth power, or 0.990.
Thus a system with a a lot of parts can end up with low reliability very
quickly. This is of course a simplified version.


Mark Walter