> > A friend of mine once built an Acorn Atom add-on that allowed him to
> > measure resistance or capacitance by timing the frequency or period of an
> > RC oscillator. For high frequencies, it's more accurate to count cycles.
> > At low frequencies, it's better to time the period.
> >
> > At some frequency between, the two methods are equally accurate.
> > He worked out this crossover point, and thus the accuracy was always
> > guaranteed better than a minimum figure.

You have to ask yourself if you want more accuracy than what you are
going
to display. By choosing your timebase properly, you only have to count
the
pulses between display updates. 50RPM, or 50.00001RPM - your car engine
is
going to stall either way!

-- 
Friendly Regards

Tjaart van der Walt
mailto:tjaart@wasp.co.za
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