List of top Sensors and Bioinstrumentation Questions on Signal Conditioning Circuits asked in GATE BM

The circuit shown below is used as an instrumentation amplifier. Among the resistors used in the input stage, the value of resistance of one of the resistors (\(R^*\)) is slightly mismatched from that of the rest of the resistors (\(R\)). Assume all operational amplifiers are ideal.
Which of the following statements is/are true?

A Hall effect flow meter is used to measure the volumetric flow through a blood vessel. The system calculated the flow rate to be 100 cm\(^3\cdot\text{s}^{-1}\). Later, calibration revealed that (i) the voltmeter was reading 40% higher than actual, and (ii) the caliper was measuring the vessel diameter 10% smaller than actual. Assuming a uniform flow profile and ignoring viscosity, the actual blood flow is _________ cm\(^3\cdot\text{s}^{-1}\) (rounded off to two decimal places).

A catheter based arterial blood pressure measurement device uses a flexible diaphragm mounted with four identical strain gauges in a Wheatstone bridge configuration as shown in the figure. Assume that the strain gauges have a nominal resistance value of \(R_G = 10\ \text{k}\Omega\), Gauge Factor \(G = 40\) and Young’s Modulus \(E = 10\ \text{MPa}\). Blood pressure variations result in small finite change in strain \(\varepsilon (\varepsilon>0)\). If \(V_o\) is the output voltage of the Wheatstone bridge and \(\sigma\) is the stress in MPa, the sensitivity \[ \frac{V_o}{\sigma} \] is ________ V.MPa\(^{-1}\).