I have a hobby project I've been developing that I want to turn into a
self assembly kit, eventually. So far google hasn't answered all my
questions about the hostility of an automobile environment. How stable
is the voltage coming off the alternator? How bad are the transients?
Are older cars worse? I assume you would see anywhere from 12-15VDC
normally depending on engine speed / alternator load, say nothing of
transients. If I was using a voltage regulator with a max 35VDC input,
is it safe to assume I would rarely see a condition to damage the
regulator? If not, what sort of input filtering should I use? Would a
"pi" http://en.wikipedia.org/wiki/Capacitor-input_filter  filter be a
good idea? Or simply a 16-30V zener diode may be enough?

My other question is temperature extremes. If I stuck with the
Microchip Industrial range, -40C to 85C, I would also assume I would
not worry about the lower limit, as cars probably have trouble
starting below -40C. The upper limit (85C, 185F) though may be
approached during summer, in the interior, in full sun (on dashboard)
and probably with a black plastic case to make the situation worse.
Does anyone know what to expect?
--=20
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