>>
Keeping the same 8V supply, is there an easy way to pre-"clip" or
pre-limit the input to approx 8V before it gets to the comparator,
but still maintaining a high input impedance?
<<

Sortof.  Maintaining high impedance within the comparator supply range is
easy.  Most comparators have some sort of input protection, usually diodes
to the supply rails.  The easiest answer is to put a large resistor in
series with the comparator so that the current thru the protection diodes
will be limited.  The impedance to the source will be high within the common
mode range, and will be the resistor value outside that range.

This scheme is not practical if the input frequency is high, because the
signal will get low pass filtered by the time it gets to the comparator.
For example, if you are sensing 60Hz power signal, then you can stick a
1Mohm resistor in series and be done with it.  However, a 1MHz signal would
probably be attenuated too much by this.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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