Ahhh, those blank, blank electrical engineers again.   Why can't it be
simple?  Current is a flowing fluid stream, just electrons not water.
Resistors are valves that increase or decrease the flow.  Capacitors are
tanks where the fluid flow is stored.   And now you are telling me the tank
size varies with age and temperature.  What are you electrical guys using
for a tank - some kind of water balloon or something?

On Wed, Jul 18, 2018 at 4:04 PM Wayne Showers <[log in to unmask]>
wrote:

> What has been described is all good information, but here is the yeah but:
>
> At design:
> Voltage coefficient is the largest concern and for this reason, each cap
> should be overtightened and then loosened.  General Rule I follow in RC
> circuits is to try to keep the capacitance as low as possible to counteract
> the effects of aging.
>
> In production testing:
> So long as the specifications are known, I use a variant of the old
> Mil-R-39008 (Carbon Comp Resistors) which is group average of 2X tolerance
> and for individuals, 3X tolerance.  This has been effective in limiting
> both bad product and test failures.  I also target testing at 60Hz for
> capacitors to limit capacitance depression from higher frequency and/or
> source impedance.
> These attributes will limit false rejections at Incoming Inspection and
> ICT.
>
> As for 'refreshing' capacitors:
> Baking above the Curie point is not always possible or for that matter
> even desirable, so I only ever did this on a limited basis.
>