I want to simulate a load cell interfacing with AD620 for amplification. - My load cell is 40 Kg max with 2mV/V sensitivity and 10 V excitation voltage with input resistance of 405 ohm and output resistance of 350 ohm as you can see. I want an output voltage ranging from 0 to 2.5 V. Using AD620 gain equation from its datasheet, I calculated Rg to be 398 ohm, I have then used a 400 ohm resistor on the simulator. First, my question is by how much should I vary R4 (strain resistor) to simulate the change in the real load cell because I am going to implement this circuit. Second, is the circuit down here correct? Regards, enter image description here

  • \$\begingroup\$ If it doesn't work on a sim then you need to investigate this - the schematic looks ok to me. \$\endgroup\$ – Andy aka May 15 '17 at 12:15
  • \$\begingroup\$ You probably need to ground-reference your bridge to give the in-amp's input biasing currents somewhere to go. No real-world in-amp will work with a completely isolated differential input like that. \$\endgroup\$ – brhans May 15 '17 at 12:43
  • \$\begingroup\$ Thanks for it, it has solve the issue. How can I know how many strain gauges does my load cell have? 1, 2 or 4? \$\endgroup\$ – idir93dz May 16 '17 at 13:50

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