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Need a comparator but don't have one?

cjdelphi

Oct 26, 2011
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Oct 26, 2011
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1,166
I've only ever built this once, but it did the job....
 

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WHONOES

May 20, 2017
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I have used opamp's as comparators. They usually require a bit of hysteresis via positive feedback to work correctly otherwise they can have a tendency to oscillate at the point of transition. As for speed that depends on the device used. But, yes proper comparators are preferable and easier to implement.
 

Alec_t

Jul 7, 2015
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If the comparator switching threshold isn't critical you can just use a single Schmitt trigger gate, e.g. CD40106, with its input resistively biased above/below the inherent threshold as required.
 

danadak

Feb 19, 2021
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Feb 19, 2021
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One drawback of CD40106 type of logic parts is they have a very low
trip accuracy for a specific valued voltage, eg. no good Vref to compare
against. As well as wide sensitivity to supply V and Temperature. You can
get comparators today with onchip Vref to solve that issue.


Regards, Dana.
 
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