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Unformatted text preview: MS-1MS-1Problem 1The temperature difference betweenposition 1andposition 2is tobe found. Letx1[290 K,310 K]denote the temperature at po-sition 1 andx2[290 K,310 K]denote the temperature at po-sition 2. Temperature at position 1 is to be measured using anintegrated temperature sensor with model functionHt-ITS(x) =xAKand temperature at position 2 is to be measured using athermistor with model functionHt-thm(x) =Re/x, whereR= 0.075 and= 3000 K.(a) Show the linear form of the thermistor model function for thegiven temperature range in which the thermistor is placed inparallel with a linearizing resistor.Thermistor with linearizing resistor:TFormula (from Set 7):Ht4(x) =RM21 +2(x-TM),whereRMis resistance at center of temperature rangeandis related to slope at center of temperature range.Call center temp,TM. From problem statementTM= 300 K.Using (provided) exponential thermistor model:RM=ReTM= 1652 .From Set 7:=-T2M=-.03333/K.MS-1EE 4770 Lecture Transparency. Formatted 13:10, 15 March 1998 from me96sol.MS-1MS-2MS-2Using the linear thermistor model function obtained above, designa circuit to convert the temperature differencex=x1-x2to voltageH(x) = xV2 K. Show all component and sourcevalues.Use a summing amp sincex1-x2is needed.+-+-RARMRTvc2voRRc2i1i2i3vc3Rc3vc1Observations:i1is a simple linear function ofx1.i2is a linear function ofx2plus a constant current.(See the thermistors linear model function.)A 1 Kelvin change inx1causes 1A change ini1.A 1 Kelvin change inx2causesz A change ini2.Solution Goals:ChooseRc2,RA, andvc2soz= 1.ChooseRc3andvc3to cancel constant current....
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This note was uploaded on 11/28/2011 for the course EE 4770 taught by Professor Staff during the Fall '99 term at LSU.
- Fall '99