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I am trying to learn how to put schematics onto a breadboard and currently I have this wheatstone bridge used for measuring the voltage change when my R2 resistor is affected by temperature.

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Now I want to put this amplifier in my circuit to make the measuring more accurate and transform the output signal. The amplifier is chosen due to high impedance and the output from op-amp should be between 0-0.5V, where 0 is room temperature.

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My question is how to actually insert this amplifier circuit into my wheatstone bridge circuit on my breadboard? If Anyone could show that would be greatly appreciated, since I tried following the image but is very unsure how to actually do it in practice. From what I understand it's supposed to be between A and B, where A is going into the op-amp and B is the output signal of it?

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  • \$\begingroup\$ If the bridge and the amplifier are built already, connect A to point marked + below the \$V_i\$ and point B to the point marked - above \$V_i\$. \$\endgroup\$
    – AJN
    Aug 25, 2020 at 12:07
  • \$\begingroup\$ I have three small amplifiers so it can be in the circuit shown above, but not implemented as the picture seen above. I assume the "bridge" is between A and B in my Wheatstone bridge? \$\endgroup\$
    – Eric Dahl
    Aug 25, 2020 at 12:16
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    \$\begingroup\$ Put a noise suppression cap across the bridge. \$\endgroup\$ Aug 25, 2020 at 12:23

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A and B go to the bridge, Vo is the output (relative to ground, or to the right-hand side of R2 if that point is not grounded).

The resistor values shown are rather low, I would suggest 10K or 20K. Rg will be determined from your desired gain. I'm not sure what the '745' op-amp is. If it's an AD745, there are probably better/cheaper choices.

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  • \$\begingroup\$ So the A should be connected to Vin, and Vo to B (on the right side of R2 like you mentioned)? Althrough, I have difficulties in knowing how to place them on my breadboard, and also how to make it all fit in my wheatstone bridge as seen in the first picture? Thank you. The book I'm following mentioned 1k to 120k Ohms was good choices, but might go with 10k resistors instead. \$\endgroup\$
    – Eric Dahl
    Aug 25, 2020 at 15:20
  • \$\begingroup\$ That’s not what I said. A goes to Vi+ and B to Vi- (or the other way around to get the opposite sign of output). Take your output from Vo on A3. \$\endgroup\$ Aug 25, 2020 at 15:24

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