A strain gauge transducer uses a Wheatstone bridge circuit to measure strain using resistance as shown...

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A strain gauge transducer uses a Wheatstone bridge circuit to measure strain using resistance as shown in Figure Q4. The maximum permissible instrument gauge current is 0.25 A. (a) (b) R Figure Q4 Outline two general types of bridge circuits and describe how strain gauge transducer can be used in a bridge circuit to measure displacement. [4 marks] At balanced condition, R =R2 R 120 2. Assuming the instrument has finite input impedance, (i) (ii) Determine the maximum permissible bridge excitation voltage. Verify that the voltage output is given by [2 marks] V = V =V (R+3 R R, +3 R+R [6 marks] When no strain is applied, show that the strain gauge resistance is given (iii) by (iv) R = RR3 R Hence, determine the nominal resistance of the strain gauge. [6 marks] If the input voltage applied is half of that calculated in Q4 (b) (i), and the output voltage at a full strain of 10 mm is 50 mV, determine the required sensitivity of the strain gauge. [7 marks] A strain gauge transducer uses a Wheatstone bridge circuit to measure strain using resistance as shown in Figure Q4. The maximum permissible instrument gauge current is 0.25 A. (a) (b) R Figure Q4 Outline two general types of bridge circuits and describe how strain gauge transducer can be used in a bridge circuit to measure displacement. [4 marks] At balanced condition, R =R2 R 120 2. Assuming the instrument has finite input impedance, (i) (ii) Determine the maximum permissible bridge excitation voltage. Verify that the voltage output is given by [2 marks] V = V =V (R+3 R R, +3 R+R [6 marks] When no strain is applied, show that the strain gauge resistance is given (iii) by (iv) R = RR3 R Hence, determine the nominal resistance of the strain gauge. [6 marks] If the input voltage applied is half of that calculated in Q4 (b) (i), and the output voltage at a full strain of 10 mm is 50 mV, determine the required sensitivity of the strain gauge. [7 marks]