PYQs Based Test - 08 : Sensors and Industrial Instrumentation

A differential capacitive sensor with a distance between the extreme plates 100 mm is shown in figure below. The difference voltage ∆V = V₁ − V₂, where V₁ and V₂ are the rms values, for a downward displacement of 10 mm of the intermediate plate from the central position, in volts, is

In the figure shown, R${}_T$ ­ represents a resistance temperature device (RTD), whose characteristic is given by R${}_T$ = R${}_O$ (1 + αT), here R${}_O$ = 100 Ω, α = 0.0039°C⁻¹ and T denotes the temperature in °C. Assuming the op-amp to be ideal, the value of V${}_O$ in volts when T = 100°C, is ________ V.

The Seebeck coefficients, in μV°C, for copper, constantan and iron, with respect to platinum, are 1.9, -38.3 and 13.3, respectively. The magnitude of the thermo emf E developed in the circuit shown in the figure, in millivolts is ________ mV.

In the circuit below, the opamp is ideal and the sensor is an RTD whose resistance R${}_{\theta }$ = 1000 (1 + 0.004θ) Ω, where θ is temperature in °C. The output sensitivity in mv/°C is ________.

A barium titanate piezoelectric crystal with d₃₃ = 150 pC/N, C${}_{crystal}$ = 25pF and R${}_{crystal}$ = 10¹⁰ Ω is used to measure the amplitude of a step force. The voltage output is measured using a digital voltmeter with input impedance 10¹³ Ω connected acorss the crystal. All other capacitances may be neglected. A step force of 2 N is applied from direction “3” on the crystal. The time in milliseconds within which the voltmeter should sample the crystal output voltage so that the drop form the peak value is no more than 0.12 V is_________