Analog Multiplexer / Switch
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Hi All,
Looking for a way to measure current in an automobile application. First
thoughts were to insert a shunt into the circuit with a very low, but known
resistance and measure the drop across the shunt. Assuming a drop in the
50-100mV range, what would be a good way to meausre that? I'd also like to
be able to measure the same at about 10-12 points. Could some sort of
analog switch be used to select a voltage source? My thoughts were to use
an analog switch (isn't the 4066 along these lines?) that could be used to
select the voltage source to be measured, but then I recall that some A/D
chips also support multiple channels. Would it be better to have multiple 4
channel A/D devices rather than a single A/D device with a 12 way switch?
All input greatly appreciated.
-- Mitch
Looking for a way to measure current in an automobile application. First
thoughts were to insert a shunt into the circuit with a very low, but known
resistance and measure the drop across the shunt. Assuming a drop in the
50-100mV range, what would be a good way to meausre that? I'd also like to
be able to measure the same at about 10-12 points. Could some sort of
analog switch be used to select a voltage source? My thoughts were to use
an analog switch (isn't the 4066 along these lines?) that could be used to
select the voltage source to be measured, but then I recall that some A/D
chips also support multiple channels. Would it be better to have multiple 4
channel A/D devices rather than a single A/D device with a 12 way switch?
All input greatly appreciated.
-- Mitch
Comments
I would question the accuracy of inserting an analog switch between the
source and measuring device; all solid state switches have some insertion
loss and possible offsets. This is especially true when measuring levels in
the millivolt range. The multichannel A/Ds would probably be better, unless
you can use mechanical switches.
My 2 cents,
Ray McArthur
> Hi All,
>
> Looking for a way to measure current in an automobile application. First
> thoughts were to insert a shunt into the circuit with a very low, but
known
> resistance and measure the drop across the shunt. Assuming a drop in the
> 50-100mV range, what would be a good way to meausre that? I'd also like
to
> be able to measure the same at about 10-12 points. Could some sort of
> analog switch be used to select a voltage source? My thoughts were to use
> an analog switch (isn't the 4066 along these lines?) that could be used to
> select the voltage source to be measured, but then I recall that some A/D
> chips also support multiple channels. Would it be better to have multiple
4
> channel A/D devices rather than a single A/D device with a 12 way switch?
Original Message
From: rjmca <rjmca@w...>
To: <basicstamps@egroups.com>
Sent: Friday, June 02, 2000 2:56 PM
Subject: Re: [noparse][[/noparse]basicstamps] Analog Multiplexer / Switch
> Mitch:
>
> I would question the accuracy of inserting an analog switch between the
> source and measuring device; all solid state switches have some insertion
> loss and possible offsets. This is especially true when measuring levels
in
> the millivolt range. The multichannel A/Ds would probably be better,
unless
> you can use mechanical switches.
>
> My 2 cents,
> Ray McArthur
>
> > Hi All,
> >
> > Looking for a way to measure current in an automobile application.
First
> > thoughts were to insert a shunt into the circuit with a very low, but
> known
> > resistance and measure the drop across the shunt. Assuming a drop in
the
> > 50-100mV range, what would be a good way to meausre that? I'd also like
> to
> > be able to measure the same at about 10-12 points. Could some sort of
> > analog switch be used to select a voltage source? My thoughts were to
use
> > an analog switch (isn't the 4066 along these lines?) that could be used
to
> > select the voltage source to be measured, but then I recall that some
A/D
> > chips also support multiple channels. Would it be better to have
multiple
> 4
> > channel A/D devices rather than a single A/D device with a 12 way
switch?
>
>