1) Which filter provides the smoothing effect over the repetitive charging & discharging phases of capacitor generated by repetitive ON-OFF action of the transistor in an inverting type of switching regulator?
a. LC filter
b. RC filter
c. R-L-C filter
d. C-L-C filter
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Answer
Explanation
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ANSWER: LC filter
Explanation:
Inverting type of switching regulator generally provides an output voltage which is absolutely opposite in polarity to that of the input voltage. By turning on the transistor with positive pulse, the inductor voltage jumps to the difference between input voltage and collector to emitter voltage in saturation region. Due to this, there is a tremendous expansion in the magnetic field of an inductor.
The diode operates in reverse-biased condition by decreasing the value of load voltage from its inceptional maximum value when the transistor operates in ON mode. Conversely, by turning OFF the transistor, magnetic field ruptures by reversal of inductor's polarity. Thus, the diode then starts operating in forward biased mode & charges the capacitor leading to the generation of negative output voltage.
Hence, it is highly feasible for L-C filter to smoothen the consequences of repetitive charging & discharging caused by frequent ON-OFF action of transistor.
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2) Commercial IC Voltage Regulators have greater significance because of their unique in-built characteristic/s like ____
a. Fold-back Current-limiting
b. Remote Control Operation
c. Self-protection against temperature
d. All of the above
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Answer
Explanation
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ANSWER: All of the above
Explanation:
IC Voltage Regulators are simple in configuration and provide fixed voltage with better quality of precision level. These IC regulators performs with greater improved features as compared to the conventional ones made from discrete components.
Some of the salient features of IC regulators include current limiting strategy, self-protection against excessive temperature along with the remote control operation for a maximum range of input voltages. Besides these, it comprises an additional feature of foldback current limiting with proficiency at functioning level.
These IC Voltage regulators are categorized into fixed & adjustable positive and negative linear voltage regulators depending on the performance & mode of operation.
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3) Which equation represents the output voltage of fixed negative linear voltage regulator?
a. VOUT = Vfixed + [(Vfixed / R1) + IQ] R2
b. VOUT = - {Vfixed + [(Vfixed / R1) + IQ] R2}
c. VOUT = Vfixed [( R1 + R2) / R2]
d. VOUT = - {Vfixed [(R1 + R2) / R2]}
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Answer
Explanation
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ANSWER: VOUT = Vfixed [( R1 + R2) / R2]
Explanation:
Fixed Negative Voltage Regulator offers a fixed level of negative voltage. Usually, 7900 series regulator with three terminal IC configuration is widely used . The capacitor (typical value of 0.22 μF) is necessary only when the location of power supply is 3 inches far from the IC regulator circuit.
Also, capacitor C2 is essential to obtain the stability of output voltage whose value is supposed to be 1μF
It is mandatory to connect the capacitor (C3) in order to ameliorate the transient response of the output voltage.
The output voltage can be generally represented by,
VOUT = Vfixed [(R1 + R2 ) / R2]
Usually, the output voltage obtained from fixed voltage negative regulator lies in the range of -5V to -12 V.
On the contrary, the output voltage of fixed positive linear voltage regulator can be adjusted within the range of 5V to 15 V and can be expressed as,
VOUT = Vfixed + [(Vfixed / R1) + IQ] R2
(Remaining equations are just meant to create perplexity)
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4) Which transistor regulator is also known as 'Emitter-Follower Regulator'?
a. Transistor Series Voltage Regulator
b. Controlled Transistor Series Regulator
c. Transistor Shunt Voltage Regulator
d. Transistor Current Regulator
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Answer
Explanation
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ANSWER: Transistor Series Voltage Regulator
Explanation:
The circuit configuration of transistor series voltage regulator is in such a manner that voltage at the emitter follows the base voltage.
Even the transistor in this type of set-up acts as a variable resistor whose value of resistance is determined by the base current. This transistor is also known as pass transistor because it allows to pass the current that needs to be regulated through it.
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5) Compute the values of VOUT & P1 in a variable feedback regulator circuit with Vin = 20V, Vz = 12V & RL = 2K if the transistor is of silicon and the wiper of R3 is adjusted in half-way configuration.
a. 16.8 V & 137.76 mW
b. 10.7 V & 80.09 mW
c. 6.7 V & 43.89 mW
d. 4.7 V & 35.79 mW
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Answer
Explanation
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ANSWER: 6.7 V & 43.89 mW
Explanation:
From the configuration of feedback regulator circuit,
VOUT = Voltage at wiper + VBE2
Voltage at wiper must be equal to half the Zener voltage since wiper is adjusted in half way configuration.
VOUT = (12 / 2) + 0.7
= 6.7 V
P1 = VCE1 x IE1
But, VCE1 = Vin - Vout
= 20 – 6.7
= 13.3 V
IE1 = IL = Vout / RL = 6.7 /2k = 3.3 mA
Therefore, P1 = 13.3 x 3.3 = 43.89 mW
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6) Which basic Op-amp regulator allows to increase the emitter voltage until the value of inverting input voltage becomes equal to Zener voltage especially when increased voltage is applied to the base of transistor?
a. Op-amp Series Regulators
b. Op-amp Shunt Regulator
c. Both a & b
d. None of the above
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Answer
Explanation
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ANSWER: Op-amp Series Regulators
Explanation:
As per the configurational arrangement, due to decrease in input voltage or load current, output voltage also tend to decrease. Thus, it is essential to apply the proportional voltage decrease to an inverting output of Op-amp using potentiometer. As another op-amp input is under the hold of Zener voltage at a fixed reference value, it gives rise to a small difference voltage across the two inputs of op-amp.
This difference voltage is also known as error voltage and it is amplified due to which the output voltage increases. Increased output voltage is further applied to the base of transistor by rising the value of emitter voltage till the inverting input voltage becomes equal to reference or Zener voltage.
This action eventually offsets attempted decrease in output voltage by maintaining it at certain value.
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7) What are the possible forms of energy transmission that can be undertaken by a transducer?
a. Acoustical
b. Electrical
c. Mechanical
d. All of the above
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8) Which parameter property defines the predictable nature of input and output relationship for maximum duration of transducer in terms of reliable operation?
a. Linearity
b. Repeatability
c. Sensitivity
d. Reliability
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9) Which active transistor results in the generation of voltage in correspondence to an illumination?
a. Piezo-electric Sensor
b. Photo-voltaic Cell
c. Thermocouple
d. All of the above
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10) Which electrical parameters are of greater significance in the selection process of a transducer?
a. Length & type of the cable
b. Limitations of frequency response
c. Signal-to-noise ratio in combination to amplifiers
d. All of the above
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11) Which reversible phenomenon in a thermocouple device exhibits the absorption and liberation of heat during flow of current through the two dissimilar copper-iron and iron-copper junctions under the application of an external e.m.f by transforming these junctions to be hot and cold respectively?
a. Seebeck Effect
b. Peltier Effect
c. Thompson Effect
d. None of the above
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12) Which among the below stated does not belong to the category of analog transducers?
a. Shaft Encoder
b. LVDT
c. Thermistor
d. Strain-gauge
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13) Which resistive elements are used to measure the combinational form of translational and rotational motions in resistance potentiometers?
a. Helipots
b. Bellows
c. Capsules
d. Bourdon tubes
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14) Determine the output voltage of a resistance position transducer when wiper is 8cm with the utilized shaft stroke level of about 20 cm from another end under the input voltage application of 10V with the total resistance value of potentiometer estimated to 6V.
a. 2V
b. 4V
c. 6V
d. 8V
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15) The bonding cement used in the fabrication process of strain gauge should possess _________
a. high insulation resistance with better strain transmissibility
b. low insulation resistance with better strain transmissibility
c. low insulation resistance with better stress transmissibility
d. high insulation resistance with better stress transmissibility
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Answer
Explanation
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ANSWER: high insulation resistance with better strain transmissibility
Explanation:
No explanation is available for this question!
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16) What kind of bonding cement is supposed to get cured instantaneously in the fabrication process of strain-gauge used as a pressure measuring transducer?
a. Duco Cement
b. Epoxy Cement
c. Acrylic Cement
d. Phenolic Bakellite Cement
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17) How is the Poisson's ratio expressed for a wire in terms of assorted directions?
a. As a ratio of strain in lateral direction to the strain in an axial direction
b. As a ratio of strain in axial direction to the strain in lateral direction
c. As a ratio of stress in axial direction to the strain in lateral direction
d. As a ratio of stress in lateral direction to the strain in an axial direction
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Answer
Explanation
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ANSWER: As a ratio of strain in lateral direction to the strain in an axial direction
Explanation:
No explanation is available for this question!
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18) Which angle of subtension can be observed by the reflected light beam during the rotational movement of mirror under the application of stress in optical gauges?
a. Equal to an angle of incident light
b. Twice to an angle of incident light
c. One-half to an angle of incident light
d. One-third to an angle of incident light
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19) Which phenomenon results in producing the difference in resistance due to incapability to regain its original physical form before an application of stress to the gauge element?
a. Hysteresis Effect
b. Barkheussan Effect
c. Differentiative Effect
d. Integrative Effect
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20) How does the value of mutual inductance vary between two coils of an inductive transducer?
a. By the variation in self-inductances and coupling coefficient
b. By the variation in number of turns
c. By the variation in reluctance and permeability
d. All of the above
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Answer
Explanation
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ANSWER: By the variation in self-inductances and coupling coefficient
Explanation:
No explanation is available for this question!
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21) What kind of electrical displacement transducers are used to measure an angular displacement?
a. Variable Resistive Transducers
b. Variable Capacitive Transducers
c. Variable Inductive Transducers
d. Synchros and Resolver Transducers
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22) How does it become possible to reduce the interference level generated corresponding to the stray magnetic fields in LVDT?
a. By Shielding
b. By Grounding
c. Both a & b
d. None of the above
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23) Which characteristics play a significant role in increasing the current flow continuously with the reduction in resistance until the heat dissipation of thermistor becomes exactly equal to the value of power supply?
a. Voltage-Time Characteristics
b. Current-Time Characteristics
c. Resistance Temperature Characteristics
d. Self-Heat Characteristics
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24) Which bridge is utilized in signal conditioning circuits for balancing purpose?
a. Maxwell Bridge
b. Wheatstone Bridge
c. Wein Bridge
d. Kelvin Bridge
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25) According to the law of intermediate metals, the thermal emf of any two metals in a homogeneous medium corresponding to third/other metal is nothing but equal to algebraic _______
a. Sum of individual e.m.fs w.r.t third/ another homogeneous metal
b. Difference of individual e.m.fs w.r.t third /another homogeneous metal
c. Sum of individual e.m.fs w.r.t third / another heterogeneous metal
d. Difference of individual e.m.fs w.r.t third / another heterogeneous metal
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Answer
Explanation
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ANSWER: Sum of individual e.m.fs w.r.t third/ another homogeneous metal
Explanation:
No explanation is available for this question!
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26) Piezo-electric crystals gets easily dissolved in ________
a. high humidity circum-ambient due to higher water solubility
b. low humidity circum-ambient due to lesser water solubility
c. high humidity circum-ambient due to lesser water solubility
d. low humidity circum-ambient due to higher water solubility
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Answer
Explanation
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ANSWER: high humidity circum-ambient due to higher water solubility
Explanation:
No explanation is available for this question!
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27) What is the major functioning role of piezoelectric transducers in spark ignition engines and electrostatic dust filters?
a. Provision of high voltage & high current electric power
b. Provision of low voltage & low current electric power
c. Provision of high voltage & low current electric power
d. Provision of low voltage & high current electric power
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Answer
Explanation
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ANSWER: Provision of high voltage & low current electric power
Explanation:
No explanation is available for this question!
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28) Which category of photo-electric transducer leads to the production of an output voltage only in accordance and proportional to the radiation intensity?
a. Photo-emissive Transducer
b. Photo-conductive Transducer
c. Photo-voltaic Transducer
d. All of the above
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29) Which device or element is/are significantly responsible for estimating or determining the accuracy level in a digital thermometer?
a. Analog to Digital Converter
b. Thermocouple
c. Scaling and Offset
d. All of the above
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30) What is the resolution range of the digitally generated temperature differences by dual slope analog-to-digital converter (ADC) in a thermocouple?
a. As small as 0.10C
b. 0.10C to 0.20C
c. 0.3C to 0.50C
d. None of the above
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31) What is the temperature measuring range of a digital thermometer in almost all kinds of environment?
a. +300C to +1000C
b. -300C to +1000C
c. +400C to + 1000C
d. -400C to +1000C
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32) A single and fundamental form of load cell which is basically used as a transducer in the operation of a weighing machine undergoes the conversion of ________
a. Force into an electrical signal
b. Pressure into an electrical signal
c. Acceleration into an electrical signal
d. Velocity into an electrical signal
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33) The occurrence of deformation in stain-gauges of a load cell under the application of pressure or strain becomes suitable for processing purpose and can be generally measured as _________
a. Mechanical signal
b. Electrical signal
c. Electrostatic signal
d. Electromagnetic signal
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34) Which significant operations are performed by the micro-processor control unit on the basis of design necessity?
a. Setting of zero adjustment level
b. Maintenance of associated statistical data
c. Provision of interfacing to a PC system
d. All of the above
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35) Why is an ac power not required in the remote areas or locations for operation purpose of two-wire transmitter?
a. Transmission power is lowered upto 4-20mA current output signal
b. Transmission power is lowered upto 1-4 mA current output signal
c. Transmission power is lowered upto 1-10 mA current output signal
d. Two-wire transmitters do not operate in remote areas
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Answer
Explanation
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ANSWER: Transmission power is lowered upto 4-20mA current output signal
Explanation:
No explanation is available for this question!
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36) How does the appearance of any noise rather than the electrical noise that intrude in the current output signal of two-wire transmitter get eliminated?
a. By common-mode rejection of transmitting device
b. By common-mode rejection of interfacing device
c. By common-mode rejection of receiving device
d. None of the above
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37) The remote mounting feature of two-wire transmitter near the sensor reduces the effects of _________
a. Noise
b. Signal Degradation
c. Both a & b
d. None of the above
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38) What is the relationship between the steady-state error, gain and the tendency of oscillations when the controller is supposed to be under the proportional action?
a. Steady-state error increases with an increase in gain and oscillation tendency
b. Steady-state error decreases with the decrease in gain and oscillation tendency
c. Steady-state error decreases with an increase in gain and oscillation tendency
d. Steady-state error increases with the decrease in gain and oscillation tendency
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Answer
Explanation
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ANSWER: Steady-state error decreases with an increase in gain and oscillation tendency
Explanation:
No explanation is available for this question!
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39) The quarter-amplitude decay ratio is basically a design criteria specified by Zeigler-Nichols method implies that the amplitude of an oscillation must be reduced by a factor of ________
a. Four over a whole period
b. Four over an half period
c. Four over a quarter period
d. Four over a quarter and a half period
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40) Which phenomenon occurs due to coincidence of two output signals generated manually as well as by control algorithm at the time of switching in manual mode?
a. Bumped Data Transfer
b. Bumpless Transfer
c. Coincidence Data Transfer
d. None of the above
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