Easa module 4 Electronic Fundamentals mcq 2

In velocity feedback the signal is
a) in phase
Ans b) out of phase
c) equal to the error signal
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When a hole diffuses from the p region to the n region
a) it becomes a minority carrier in the n region
b) lowers the potential barrier
Ans c) raises the potential barrier
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A junction diode
Ans a) has one p-n junction
b) is similar to a vacuum diode but cannot rectify

c) can handle only small currents
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The rotor of a magnesyn transmitter is
a) a dc electromagnet
Ans b) a permanent magnet
c) an ac electromagnet
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In general the accuracy of a synchro system increases if the
a) stator current is high
Ans b) stator current is low
c) rotor current is high
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Torque synchro systems are normally used when the
Ans a) mechanical load is low
b) mechanical load is high
c) system accuracy is of extreme importance
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In a resolver synchro the stator windings are electrically disposed by
Ans a) 90o
b) 120o
c) 180o
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The induced signal in the output coils of the magnesyn system
a) de-saturates the soft iron core
b) damps the pointer oscillations
Ans c) is of a value of 800 Hz
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The direction of the induced (secondary) magnetic field in a synchro transmitter
a) is 90o to the primary magnetic field
b) in the same direction as the primary field
Ans c) is in the opposite direction to the primary field
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The cogging effect in synchros is rectified by
a) using carbon brushes
b) using an elliptical cog
Ans c) skewing the rotor
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A transistor is said to be in the quiescent state when
Ans a) no signal is applied to the input
b) it is unbiased
c) no currents are flowing
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In an unbiased p-n junction, current flow is
a) due to the diffusion of minority carriers only
Ans b) zero, because no charges are crossing the junction
c) zero, because equal but opposite currents are crossing the junction
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Reversal of the power supply to either the transmitter or the receiver of a torque synchro system would
Ans a) cause a 180o displacement between the transmitter and the receiver
b) have no effect on the indication, but would cause a heavy current to flow
c) make the receiver rotor rotate in the opposite direction
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Torque synchro systems are normally used when the
Ans a) mechanical load is low
b) mechanical load is high
c) system accuracy is of extreme importance
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A common base transistor circuit is so called because
a) the base region is located between the emitter and collector region
b) the base is n-type material
Ans c) the base is common to the emitter and collector circuits
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What device transfers one energy type to another?
a) Transmitter
Ans b) Transducer
c) Transponder
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Which way does conventional current flow in a PNP junction?
a) Collector to emitter
Ans b) Emitter to base
c) Collector to base
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Electrical power is supplied to a synchro rotor
a) directly
Ans b) through slip rings
c) through a commutator
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The purpose of a flywheel incorporated in a synchro is to
a) increase the driving force
Ans b) prevent oscillations
c) prevent insect ingress
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In an operational amplifier, the two input waves are the same amplitude, same frequency, but exactly anti-phase. What would the output be?
Ans a) Double
b) Zero
c) Half
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A thyristor has which of the following?
a) High resistance when switched on
Ans b) High resistance when switched off
c) A positive temperature coefficient
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On an integrated circuit the hole in the top left corner is pin 1. The pins are counted
a) clockwise
Ans b) anticlockwise
c) from left to right
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With reference to the circuit shown below, how is the transformer configured?
Ans a) Common emitter
b) Common collector
c) Common base
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In the circuit diagram above, R1 and R2 are used to
a) set the transistor gain
Ans b) set the DC bias level
c) increase the base voltage
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In a synchro system, if two stator lines are crossed the receiver will
a) not be affected
b) be 180o out
Ans c) reverse direction
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