current sensor circuit
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I need a circuit that senses current of .2A and sends out a voltage when the
current is sensed.
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current is sensed.
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Comments
Or, do you want to measure a range from 0 to 200 mA and then change
that to a 0 to 4.096 voltage so that it can be read with a A/D
converter?
Your best to use a current sense resistor and add a op amp in there
for gain.
LEM makes current sense modules and are available from Digikey. They
are kinda pricey at $25 each, but it is an off the shelf solution.
Maxim makes a few current sense monitor IC's.
MAX472 should work nicely and comes in a plastic 8 pin dip, and you
can request free samples. It is programmable via external resistors.
http://pdfserv.maxim-ic.com/en/ds/MAX471-MAX472.pdf
Jason
--- In basicstamps@yahoogroups.com, Steve Platovskiy <plato012@y...>
wrote:
> I need a circuit that senses current of .2A and sends out a voltage
when the current is sensed.
>
>
>
> Do you Yahoo!?
> Yahoo! SiteBuilder - Free, easy-to-use web site design software
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
as low as possible to reduce losses. the comparitor can be set for
any current you want.
an op-amp instead of a comparator and you can feed an RC network for
RCtime for a sloppy and low quality analog value.
should offer 1/4-1/2-3/4 or full values.
Dave
--- In basicstamps@yahoogroups.com, Steve Platovskiy <plato012@y...>
wrote:
> I need a circuit that senses current of .2A and sends out a voltage
when the current is sensed.
>
>
>
> Do you Yahoo!?
> Yahoo! SiteBuilder - Free, easy-to-use web site design software
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
as 0.2 Amp a.k.a. 200 milliamps? There are some simple current transformers
you can wind yourself if it's A.C., but they won't work for D.C.
Otherwise, Dave's recommendation of a resistor and comparator or op-amp
works fine for D.C. circuits. But with large currents you can lose a lot of
power to heat conversion. It's that old law of Voltage x Current = Wattage.
Hmmmmmmm.... I'm having a brainstorm that you might use a Kelvin 4-wire
bridge sort of in reverse (with a known fixed resistance) to provide a more
accurate voltage output using a very low resistance value, perhaps even the
resistance of the feed wire itself.
I'll muse on this a bit. Any thoughts???
Mike Sokol
www.modernrecording.com
mikes@m...
301-739-6842 voice/fax
301-964-5682 mobile
Original Message
From: "Dave Mucha" <davemucha@j...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, September 10, 2003 11:02 PM
Subject: [noparse][[/noparse]basicstamps] Re: current sensor circuit
> considder a comparitor with a resitor on the load. make the resistor
> as low as possible to reduce losses. the comparitor can be set for
> any current you want.
>
> an op-amp instead of a comparator and you can feed an RC network for
> RCtime for a sloppy and low quality analog value.
> should offer 1/4-1/2-3/4 or full values.
>
> Dave
>
>
>
>
>
> --- In basicstamps@yahoogroups.com, Steve Platovskiy <plato012@y...>
> wrote:
> > I need a circuit that senses current of .2A and sends out a voltage
> when the current is sensed.
> >
> >
> >
> > Do you Yahoo!?
> > Yahoo! SiteBuilder - Free, easy-to-use web site design software
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
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