Pressure tranducer Circuit help!!

rupash88

Jun 21, 2005
6
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Jun 21, 2005
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6
Hi, im doing a project for my university which goes towards my qualification..and am stuck on designing a circuit that thats a pressure transducer which im replicated as a wheat stone bridge, into an offset circuit. Im just having difficulties finding or making a good off set circuit ???. Any help would get greatly appriciated. thanks ;D

 

heathtech

Jun 6, 2005
60
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Jun 6, 2005
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60
  I'm not exactly sure what you need here, please go into more detail.
  As far as a wheatstone bridge goes, I can help you with that. Do you know what a strain gauge is? It is a pressure transducer that varies resistance in a linear fashion when pressure is applied, and can be installed on one side of a Wheatsone Bridge. Do you understand the function of a Wheatstone bridge? Do you need a tutorial on that? Please tell me what you understand and I can help you.

 

rupash88

Jun 21, 2005
6
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Jun 21, 2005
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6
My apologies if i was clear...i making a manometer, and basically have a made a wheat stone bridge to mimic my transducer so that i dont screw my ($100 :() transducer up. And im adding a differential opamp in front for some gain but also with offset capabilities, so that i can adjust a pot to zero that display if it drifts. Im then feeding it to 3 opamps which will have gain to represent the 3 settings that i want to switch to (PSI, mmHG, and Kpa).

Im just having difficulties on making the gain/offset circuit that is feed from the transducer, so basically looking for offset/gain circuits. Thanks for your time.

 

NSklavos1

Jun 14, 2005
4
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Jun 14, 2005
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4
I have used the following circuits to null out offsets on wheatsone bridge circuits. The first circuit just puts a resistor in parallel with one branch of the bridge allowing any offset to be adjusted out. R Offset value can be calculated by figuring out parallel resistance needed to compensate for the bridge offset when the pot is at either extreme of it's range (i.e. R Offset will be either tied to +V or -V/Gnd).

The second circuit just uses an op amp in a voltage mixer configuration. The potentiometer can be any value (10k ohm works OK). R Offset can be calculated by figuring out how much offset you need to adjust for and the votage gain of the op amp.

View attachment 37390

 
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