I did try to connect it to a wheatstone bridge. I think the opamp was in th= e saturation region. It responded only for certain loads. I am awaiting a D= C-DC converter to set the opamp in rail to rail configuration. I measured the sensor with no load and it was approximately 10K ohms. So I = put it in a 10 K Ohm bridge based on my theoretical knowledge. Is this the = right way to do it?=A0 I had an INA826 Instrumentation amplifier evaluation board and I used one o= f the examples available with the board to connect the bridge. =A0 Sai ________________________________ From: "jim@jpes.com" To: Microcontroller discussion list - Public. =20 Sent: Wednesday, February 13, 2013 8:28 AM Subject: RE: [EE]: Opamp based circuit design =20 Why don't you connect the sensor in a wheatstone brisge configuration.=20 That would make small changes in resistance very obvious.=A0 You could then use an opamp to boots the output levels and put them in the range of the A2D you are using. Jim Regards, Jim > -------- Original Message -------- > Subject: [EE]: Opamp based circuit design > From: yamanoor sairam > Date: Tue, February 12, 2013 8:09 pm > To: "Microcontroller discussion list - Public." >=20 >=20 > Hi All, >=20 > I am using a=A0Fabric Pressure sensor=A0in my project that could be read = using a potential divider arrangement. =A0 >=20 > Due to the hysteresis, the change in resistance is really small when this= sensor is subjected to several cycles of stress/strain.=A0 >=20 > Another disadvantage behind using the sensor is that there is a sudden ch= ange in resistance when the fabric is stretched/contracted.=A0 >=20 > I am planning to designing an op-amp circuit with a gain of 10, rail to r= ail configuration to detect small changes in resistance and get rid of larg= e changes. =A0Is this the only way to do it? >=20 > I thought I should check this with someone before buying the components. = I tried a unity gain amplifier and I was not successful.=A0 >=20 > Thanks, > Sai > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .