EASA module 4 Electronic Fundamentals mcq 4

An LVDT has
Ans a) an output winding which is wound in series opposition
b) an input winding whose voltage will change with load movement
c) an output winding whose voltage and frequency is linear to load angular movement
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A diode connected across a relay coil is used to
a) allow the coil to energize with only one polarity
b) cause a delay in switching on
Ans c) dissipate coil spikes on switch off
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Differential transmitters are used to
a) add or subtract two electrical signals
Ans b) add or subtract a mechanical signal to an electrical synchro signal
c) increase the operating speed of the synchro receiver
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To convert a differential synchro from subtraction to addition you would
a) reverse the reference phase supply
Ans b) change over two rotor and stator connections
c) change over all three stator windings
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What is resistor R used for?
a) Amplification
b) Bias
Ans c) Stabilisation
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When resolving a Cartesian input to a Polar output
a) the inputs are a shaft angle and a voltage
b) the outputs are two voltages
Ans c) the inputs are two voltages
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To check the forward resistance of a diode with a multimeter, the lead connected to the positive terminal is put to the
Ans a) anode
b) cathode
c) either anode or cathode
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A resolver synchro output is obtained from a rotor with
a) one single coil
Ans b) two coils at 90o to each other
c) three coils at 120o to each other
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The input and output signals of a common emitter amplifier are
a) equal
Ans b) out of phase
c) in phase
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The output of a resolver synchro is
a) dependant upon the position of the rotor only
b) proportional to the speed of input rotation
Ans c) a function of the rotor position and excitation voltage
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The rotor of an autosyn position indicating system is
a) a permanent magnet
Ans b) an electromagnet
c) spring controlled
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A band pass filter excludes frequencies
a) above the frequency required only
b) below the frequency required only
Ans c) above and below the frequency required
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A resolver synchro output is obtained from a rotor with
a) one single coil
b) three coils at 120o
Ans c) two coils at 90o
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In a control synchro the stator current ceases to flow when
a) the CT rotor is at null
b) when the two rotors are aligned
Ans c) when power is removed
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In a speed control servo system (rate control), the purpose of the tachogenerator is
a) to make the velocity proportional to servo demand
b) to make the deflection proportional to servo demand
Ans c) to make it run at constant speed
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The result of reversing the rotor connections to the receiver of a torque synchro system is that the rotor position
a) is unchanged
b) is changed by 120o
Ans c) is changed by 180o
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The rotor of a torque synchro indicator is
Ans a) supplied with an excitation voltage
b) short circuited
c) connected in series with the transmitter stator coil
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When a hole diffuses from a p-region to the n-region it
a) becomes a minority carrier in the n-region
b) lowers the potential barrier
Ans c) raises the potential barrier
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How are the pins numbered on an op-amp IC?
Ans a) counter clockwise from the dot
b) clockwise from the dot
c) from left to right from the dot
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To increase the output of a servo amplifier, it is necessary to
Ans a) reduce the tacho feedback
b) increase the tacho feedback
c) increase the position feedback
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