>>  A couple more things need to be known before anyone can really give you an
 >>  answer.
 >>  1) Are we assuming p-p freq. to be within audio range?

any freq, we are dealing with audio range freq however, so it should work for =
20-15k range

 >>  2) How long does the LED have to sustain after receiving threshold?

well could just blink for the instant it happens, might be nice to have it stay =
on for 0.25 - 0.5s

 >>  3) Are you planning to use a PIC to do the detecting? (overkill really)

no opamp / comparator

 >>  4) Do you want to detect on > +.2 and/or -.2v?

yes

 >>  5) We need to know if you are wanting to mix analog with digital to
 >>  achieve your goal, or straight analog citcuitry.

hopefully its just analog

 >>  There are many sample circuits in the National Linear Databooks and
 >>  application notes that will probably provide what you want. A simple
 >>  opamp will achieve your
 >>  desired results. A Norton Amp such as the LM3900 will probably work and
 >>  will operate from 4v to 36v single ended supply. You'll have to dig
 >>  around for a sample
 >>  circuit in the databooks, but they're there. Otherwise someone on the list
 >>  might be patient enough to walk you through a working circuit.

I have looked and seen non in national book.... i can look again!

And I agree on patience as question after  question on here needs answering and =
you could have a full time job just answering!

Thanks!

 >>  Rick

 >>  Richard Sloan wrote:

 >>  > I have a signal that is 0.4vp-p and is 0 volt based (0.2 up 0.2 down) I
 >>  want to detect with a LED that lights when the limit is exceeded. This is
 >>  0.4Vp-p limit.
 >>  >
 >>  > I only have 0-5V available power?
 >>  >
 >>  > Can this simply be done with a comparator?
 >>  >
 >>  > Any help is appreciated.
 >>  >
 >>  > Richard.
 >>  >
 >>  > --
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 >>  --
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