rupash88 Posted July 19, 2005 Report Share Posted July 19, 2005 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 Quote Link to comment Share on other sites More sharing options...
heathtech Posted July 19, 2005 Report Share Posted July 19, 2005 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. Quote Link to comment Share on other sites More sharing options...
rupash88 Posted July 22, 2005 Author Report Share Posted July 22, 2005 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. Quote Link to comment Share on other sites More sharing options...
NSklavos Posted July 25, 2005 Report Share Posted July 25, 2005 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. Quote Link to comment Share on other sites More sharing options...
rupash88 Posted July 29, 2005 Author Report Share Posted July 29, 2005 Thanks alot! will fiddle around with that when I spend time on it. Quote Link to comment Share on other sites More sharing options...
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