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Everywhere it seems to be taken for granted that a Wheatstone bridge is more precise, accurate etc. I don't see why it would be any better than a voltage divider if I am directly measuring the voltage across the resistor in both cases.

Especially these days when we can simply use an instrumentation amplifier for measuring the differential voltage which will provide minimal loading, will a bridge configuration provide any specific advantage over a simple voltage divider?

JRE
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needbrainscratched
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  • I did go through that before asking here but it didn't help much. I am looking for a more direct technical explanation of whether there is any reason to keep using them. It seems to me that it's more of a convention than anything else. – needbrainscratched Jun 10 '21 at 07:25
  • it's not just a convention! (I don't think engineers think lots in conventions when designing - we sometimes work with design patterns, using "known to work well" approaches and only marginally fitting them to the problem; conventions are *very* important when communicating things, though). You'll have to please point to an example of a wheatstone bridge *actually* being used where an instrumentation amplifier could or even should have been used, maybe it's easy to generalize from there! – Marcus Müller Jun 10 '21 at 07:32
  • I'm really not convinced that this is "almost always" used. Personally, I haven't used a Wheatstone bridge in ... ages. So, maybe your perception of it being "always" used is a bit skewed? – Marcus Müller Jun 10 '21 at 09:07
  • In all the documentation I found regarding resistive sensors, all of them used wheatstone bridge with the differential voltage given to an INA with additional circuitry for linearisation, offset compensation etc. If you find any application where a voltage divider or any other configuration is used please share the documentation with me! – needbrainscratched Jun 10 '21 at 09:48
  • can you please link to at least one of these documentations? You're claiming something is done "all the time", and I haven't seen a single thing we can discuss about *why* it might be done that way. It's not our job to produce counterexamples to your claims. – Marcus Müller Jun 10 '21 at 09:52

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One compelling reason that comes to mind is that many opamps don't like their input near to the voltage rails. There's also a few 24bit adcs that don't like it as well. The ADUC0841 comes to mind. Being differential in, the wheatstone bridge configuration just works.

Kartman
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