2 wire strain gauge amplifier module -

1

Hello All,

I’ve got a 5V available and need to develop a circuit design to read voltage changes when a strain gauge experiences very little strain. However, using a regular Wheatstone bridge is not enough as the changes in strain&voltage are too low.

What would be a good amplifier module for a 2 pin strain gauge?

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Cheers,
Indi

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2

Hi Indi,

Interesting question, how much strain were you looking to measure?

There are a few reference circuits in the installation manual on the RS components page for the product, one with a gain of 1000
I’d say getting a very very sensitive reading would be more in the realm of an engineered solution.
Liam.

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3

Hi Liam,

About 5mm of deflection in the material it will be embedded in.
I am still running experimentation so the actual strain experienced is a slight unknown.

My point of reference are the changes in resistance and voltage which in this case is around 1 ohm and 30-60mV - Does that help?

Indi

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4

Hey Indi,

The purpose of a wheatstone bridge is to compensate for temperature and other effects. What do you mean when you say the change is not enough?

The change in resistance of an individual strain gauge element is minute - hence the requirement for strain gauge amplifiers. What precisely are you attempting to achieve?

Strain is a ratio - units of mm/mm, or unitless depending how you think about it. A deflection of 5mm doesn’t mean much by itself.

Edit: Here’s a pretty good article explaining the application of a wheatstone bridge to strain measurement:

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