GATE 2017-2018 :: GATE Instrumentation
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The circuit below incorporates a permanent magnet moving coil milli-ammeter of range 1 mA having a series resistance of 10 kΩ. Assuming constant diode forward resistance of 50 Ω, a forward diode drop of 0.7 V and infinite reverse diode resistance for each diode, the reading of the meter in mA is
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Measurement of optical absorption of a solution is disturbed by the additional stray light falling at the photo-detector. For estimation of the error caused by stray light the following data could be obtained from controlled experiments. Photo-detector output without solution and without stray light is 500 μW.Photo-detector output without solution and with stray light is 600 μW.Photo-detector output with solution and with stray light is 200 μW.The percent error in computing absorption coefficient due to stray light is
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Two ammeters A1 and A2 measure the same current and provide readings I1 and I2 , respectively. The ammeter errors can be characterized as independent zero mean Gaussian random variables of standard deviations σ1 and σ2 , respectively. The value of the current is computed as : I = μ I1 + (1 - μ) I2The value of μ which gives the lowest standard deviation of I is
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A tungsten wire used in a constant current hot wire anemometer has the following parameters : Resistance at 0° C is 10Ω, Surface area is 10-4 m2, Linear temperature coefficient of resistance of the tungsten wire is 4.8 * 10-3 /°C, Convective heat transfer coefficient is 25.2W / m2 /°C, flowing air temperature is 30°C, wire current is 100 mA, mass-specific heat product is 2.5 * 10-5 J /°CThe thermal time constant of the hot wire under flowing air condition in ms is
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A tungsten wire used in a constant current hot wire anemometer has the following parameters : Resistance at 0° C is 10Ω, Surface area is 10-4 m2, Linear temperature coefficient of resistance of the tungsten wire is 4.8 * 10-3 /°C, Convective heat transfer coefficient is 25.2W / m2 /°C, flowing air temperature is 30°C, wire current is 100 mA, mass-specific heat product is 2.5 * 10-5 J /°CAt steady state, the resistance of the wire in Ω is
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A piezo-electric force sensor, connected by a cable to a voltage amplifier, has the following parameters : Crystal properties : Stiffness 109 N/m, Damping ratio 0.01, Natural frequency 105 rad/s, Force-to-Charge sensitivity 10-9 C/N, Capacitance 10-9 F with its loss angle assumed negligibleCable properties : Capacitance 2 × 10-9 F with its resistance assumed negligibleAmplifier properties : Input impedance 1 MΩ, Bandwidth 1MHz , Gain 3The maximum frequency of a force signal in Hz below the natural frequency within its useful midband range of measurement, for which the gain amplitude is less than 1.05, approximately is,
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A piezo-electric force sensor, connected by a cable to a voltage amplifier, has the following parameters : Crystal properties : Stiffness 109 N/m, Damping ratio 0.01, Natural frequency 105 rad/s, Force-to-Charge sensitivity 10-9 C/N, Capacitance 10-9 F with its loss angle assumed negligibleCable properties : Capacitance 2 × 10-9 F with its resistance assumed negligibleAmplifier properties : Input impedance 1 MΩ, Bandwidth 1MHz , Gain 3The minimum frequency of a force signal in Hz within its useful mid-band range of measurement, for which the gain amplitude is more than 0.95, approximately is,
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Consider a plant with the transfer function G(s) = 1/(s + 1)3. Let Ku and Tu be the ultimate gain and ultimate period corresponding to the frequency response based closed loop Ziegler-Nichols cycling method, respectively. The Ziegler-Nichols tuning rule for a P-controller is given as : K = 0.5 Ku. The values of Ku and Tu, respectively, are
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Consider a plant with the transfer function G(s) = 1/(s + 1)3. Let Ku and Tu be the ultimate gain and ultimate period corresponding to the frequency response based closed loop Ziegler-Nichols cycling method, respectively. The Ziegler-Nichols tuning rule for a P-controller is given as : K = 0.5 Ku. The gain of the transfer function between the plant output and an additive load disturbance input of frequency 2Ï€/Tu in closed loop with a P-controller designed according to the Ziegler-Nichols tuning rule as given above is
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A differential amplifier with signal terminals X,Y,Z is connected as shown in Fig. (a) below for CMRR measurement where the differential amplifier has an additional constant offset voltage in the output. The observations obtained are: when Vi = 2 V, V0 = 3 mV, and when Vi = 3 V, V0 = 4 mV
Assuming its differential gain to be 10 and the op-amp to be otherwise ideal, the CMRR is
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