Module 4 v
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1. A junction diode
a) has one p-n junction
b)is similar to a vacuum diode but cannot rectify
c) can handle only small currents
2. A germanium diode is used for
a) voltage stabilisation
b)rectification
c) signal detection
3. A germanium diode
a) has a lower forward bias voltage than a silicon diode
b)has a higher forward bias voltage than a silicon diode
c) has the same forward bias voltage as a silicon diode
4. a VLSIC has
a) less than 1000 gates
b)more than 1000 gates
c) more than 10,000 gates
5. A momentary input at the reset input of a flip flop will
a) reset the true output to 0
b)reset the true output to 1
c) clock in new data from the data inputs
6. Which type of flip flop has only 1 data input
a) RS
b)JK
c) D
7. A low pass filter has
a) a capacitor in series and an inductor in parallel
b)a capacitor in parallel and an inductor in series
c) both capacitor and inductor in parallel
8. When you use an op amp as a buffer it has
a) high input impedance and low output impedance
b)low input impedance and high output impedance
c) the same input an output impedance
9. What switches off a thyristor?
a) Remove the gate voltage
b)Remove supply voltage
c) Reverse bias gate
10. When an SCR is switched on it has
a) high resistance
b)low resistance
c) no change in resistance
1. What is required for the switching of a monostable multivibrator
a) one trigger pulse to switch on and another to switch off
b)one trigger pulse to both switch on and off
c) one trigger pulse to switch on and two trigger pulses to switch
off
2. A transistor at saturation has
a) high resistance
b)low resistance
c) zero resistance
3. A capacitor resistor coupled multistage amp lets
a) AC and DC pass to the next stage
b)AC pass only
c) DC pass only
4. An oscillator operating at its natural frequency has feedback which
is
a) inphase
b)90 degrees out of phase
c) 180 degrees out of phase
5. What type of diode when forward biased holes and electrons recombine
producing photons?
a) gunn
b)LED
c) photodiode
6. What type of pulse is required to switch on a SCR
a) positive
b)negative
c) positive and negative
7. Which mathematical operation is performed by a modulator amplifier?
a) Addition
b)Subtraction
c) Multiplication
8. What is meant by a bistable circuit?
a) The circuit has 2 stable states and will stay in which one it is put
b)The circuit has 2 stable states and will stay in both at the same
time
c) The circuit has 1 stable state and it can be negative or positive
9. A zener diode is designed to operate
a) above its breakdown voltage
b)below its breakdown voltage
c) either above or below its breakdown voltage
10. A JFET is
a) voltage sensitive
b)current sensitive
c) either of the above depending on resistance in the circuit
1. A triac is a type of
a) thyristor
b)thermistor
c) transistor
2. A piece of pure Germanium
a) has a deficit of electrons
b)is electrically stable
c) has an excess of electrons
3. If a junction diode is reverse biased too far, the output current
would
a) cease to flow
b)increase
c) reverse direction
4. An RC connected amp has
a) no AC across
b)no DC across
c) even amounts of d.c and a.c across
5. When a PN junction is forward biased, it conducts via
a) majority carrier
b)minority carrier
c) intrinsic carrier
6. Thermal runaway in a transistor refers to
a) high current flow when temperature increases
b)low current flow when temperature increases
c) high current flow when temperature decreases
7. When is maximum voltage induced into the rotor of a control synchro
transformer?
a) 90 degrees (null position)
b)0 degrees
c) When spinning fast
8. Resistors and capacitors are used to couple stages of amplifiers so
that
a) only d.c can be applied
b)equal amounts of a.c and d.c can be applied
c) only a.c can be applied
9. An astable multivibrator is a
a) free running vibrator
b)one which requires an input to switch on and off
c) one which requires no input whatsoever
10. Op amps use what power supply?
a) 26v a.c
b)5v - 15v d.c
c) 26v d.c
1. To check the output of a synchro stator it would be preferable to use
a) an Avometer
b)a Valve Voltmeter
c) a Cambridge Bridge
2. Synchro capacitors are connected into synchro systems to
a) minimize the torque synchro stator current at null
b)increase the accuracy of the control synchro
c) act as spark suppression due to wear of the slip rings
3. The purpose of the fly wheel incorporated in a synchro
a) is to increase the driving force
b)to prevent oscillations
c) to prevent insect ingress
4. In a slab desynn transmitter the
a) pick-offs form part of the circuit resistance
b)pick-offs rotate on the slab resister
c) pick-offs are connected to a spark suppressor
5. If, in a servo system, the amplitude from the feedback system is
below normal, the servo will
a) oscillate
b)be sluggish in operation
c) be overdamped
6. A desynn instrument has a positive irregular increasing error, you
would adjust
a) lever length
b)lever angle
c) lever angle and lever length
7. Torque synchro receiver bearing friction will cause
a) hunting
b)misalignment
c) improved accuracy
8. A control synchro system pointer is
a) actuated by a permanent magnet
b)displaced by the torque of the stator
c) motor driven
9. A D.C. signal converted to a phase sensitive A.C. is
a) demodulation
b)phase conversion
c) modulation
10. If velocity feedback in a servo system is above optimum, this will
cause
a) sluggish operation
b)hunting
c) has no effect
1. A device which has a high input impedance, low output impedance and
high voltage gain is a
a) Class A amp
b)Class B amp
c) Op-Amp
2. In an integrated circuit, the components are mounted by
a) wires connecting them using conformal coating
b)a three dimensional process with no connections between them required
c) metal oxide film etched onto surface
3. For a NPN transistor to conduct the collector circuit has to be
a) more positive than the emitter
b)more positive than the base
c) less positive than the emitter
4. The amount of rate feedback from a tachogenerator is
a) proportional to speed
b)inversely proportional to speed
c) constant for all servo speeds
5. When forward biased, current flow is mainly due to the
a) majority carriers
b)minority carriers
c) germanium bias junction
6. When forward biased the
a) positive lead is connected to the N type and negative to the P type
b)positive lead is connected to the P type and negative to the N type
c) positive lead is connected to both N and P type
7. In a PNP transistor, which way does conventional current flow?
a) Base to emitter
b)Collector to emitter
c) Emitter to Collector
8.
In the Zener Diode suppressor shown, point X in respect to point Y should
be
a) more negative
b)more Positive
c) either positive or negative
9. In an integrated circuit, the components are inserted
a) manually
b)automatically
c) by doping in successive layers
10. The typical voltage drop across an L.E.D is
a) 2V
b)4V
c) 6V
1. In an electronic circuit with an operational amplifier connected in
the push-pull configuration, the circuit
a) decreases impedance
b)utilizes both sides of the input signal
c) blocks half of the input signal
2. Pin 3 on an op-amp has a + symbol. This designates
a) positive offset null
b)positive input DC pin
c) non-inverting input
3. An advantage of a FET when compared to a bi-polar transistor is
a) the input resistance is lower
b)the switching time is quicker
c) the input resistance is higher
4. The semiconductor substrate used in 'chips' is most commonly
a) germanium
b)silicon
c) phiidide
7. What control system is used on an input that gives a controlled
predetermined output?
a) Open Loop
b)Closed Loop
c) Control Servo
__________________
Homer not function well beer without !
Module 4 vi
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8. Increasing velocity feedback from optimum will give
a) sluggish performance
b)faster performance
c) no change on the output
9. A rate control servo system with a steady input voltage will give
a) constant speed
b)increasing speed
c) decreasing speed
10. Where are decoupling capacitors used in digital circuits?
a) Between pins 1 & 8
b)Close to the +ve pin
c) Close to the –ve pin
1. What are the majority carriers for a forward biased PN junction
device?
a) Electrons
b)Holes
c) Electrons and holes
2. The resistance measured using an AVO between the Collector and
Emitter of a transistor is
a) same both ways
b)smaller Collector to Emitter
c) higher Collector to Emitter
3. Germanium in its pure state is
a) neutral
b)positively charged
c) negatively charged
4. Common Collector has the following characteristics
a) Medium Voltage Gain, High Current Gain, Non-Inverted Output
b)Low Voltage Gain, High Current Gain, Inverted Output
c) Medium Voltage Gain, Low Current Gain, Inverted Output
5. Two push-pull transistors have what commoned?
a) Bases
b)Collectors
c) Emitters
6. In a Common Emitter Amplifier RE is used for
a) biasing
b)stabilisation
c) load control
7. If the reverse bias voltage across a diode is too high
a) load current increases rapidly
b)load current reverses
c) load current reduces to zero
8. The rotor coil of a synchrotel
a) is stationary
b)rotates
c) rotates only when a current flows in it
9. An increase in amplitude of a rate feedback signal will cause
a) sluggish servo operation
b)reduced hunting
c) instable operation
10. An increase in negative feedback
a) increases system sensitivity
b)decreases system sensitivity
c) will make the driven device continuously rotate
1. An integrated circuit is manufactured by
a) computer hardware, which use individual circuits on ribbon
b)doping impurities into layers of intrinsic material
c) etching copper tracks onto an insulating board
2. A de-coupling capacitor in a PCB is used to
a) minimise transient currents
b)pass a.c only
c) pass d.c only
3. A monostable vibrator
a) is switched on by a trigger pulse then within a pre-set time will
eventually return to its original state
b)uses a trigger pulse to turn on and the same pulse to turn off
c) uses one pulse to turn on and another to turn off
4. Position feedback is used to
a) ensure control surface moves to the demanded position by the
controls
b)to prevent control surface oscillations while the surface is being
moved
c) indicate to the pilot the position of the load
5. The output from a control transformer is
a) torque
b)AC voltage
c) DC voltage
6. The stator output voltages from a synchro resolver are
a) DC
b)AC single phase
c) 3 phase
7. The purpose of synchro capacitors in a differential synchro
transmission system
a) to reduce stator current
b)reduce rotor current
c) reduce stator circuit impedance
8. A typical use for resolver synchros is
a) in compass comparitor units
b)engine power instrumentation
c) fly by wire system
9. The purpose of a flywheel in a synchro receiver indicator is to
a) prevent spinning or oscillation
b)encourage spinning
c) increase driving torque
10. A linear variometer is
a) a special synchro giving ac output proportional to shaft angle
b)a special auto transformer for synchro system power supplies
c) an alternative term for a desynn system
1. In a synchrotel the rotating winding is
a) the stator
b)rotor
c) neither
2. The receiver rotor in a torque synchro system oscillates over an arc
of approx 75 degrees. The probable cause is
a) short circuit between two stator lines
b)two stator lines reversed
c) one stator line open circuit
3. Synchro capacitors are fitted
a) to provide critical damping
b)to make additional damping features unnecessary
c) to improve sensitivity and accuracy
4. The output of a control transformer is made
a) phase and amplitude sensitive by direction and magnitude of the
transmitter rotor movement respectively
b)phase and amplitude sensitive by magnitude and direction of the
transmitter rotor movement respectively
c) phase sensitive by transmitter rotor excitation and amplitude
sensitive by direction of transmitter rotor movement
5. A transistor is used in
a) current amplifier
b)voltage amplifier
c) both
6. An LED which emits green light uses
a) gallium ****nide phosphide
b)gallium phosphide
c) gallium ****nide
7. An LED which emits red light uses
a) gallium ****nide phosphide
b)gallium phosphide
c) gallium ****nide
8. A photodiode is operated under
a) reverse bias conditions
b)forward bias conditions
c) reverse or forward bias conditions
9. To increase capacitance of a varactor diode
a) reverse bias voltage is increased
b)forward bias voltage is decreased
c) reverse bias voltage is decreased
10. Which diode has a lower forward bias voltage?
a) silicon
b)germanium
c) both the same
1. A Zener diode is used for
a) rectification
b)voltage stabilisation
c) voltage regulation
4. A thyristor SCR is a
a) unidirectional device
b)bi-directional device
c) multidirectional device
5. A bi-directional TRIAC has two SCRs connected in
a) series parallel
b)parallel series
c) inverse parallel
6. A thyristor can be forward biased by
a) positive pulse
b)negative pulse
c) positive or negative pulse
7. 'N' type materials are doped with
a) acceptors
b)donors
c) acceptors and donors
8. A junction diode if reverse biased too far, the output will
a) increase
b)stop
c) reverse
9.
The input of this circuit will be
a) integrated
b)differentiated
c) logarithmic
10. The most suitable class of amplifier for a radio transmitter is
a) A
b)B
c) C
2. What is the base material of a PCB?
a) Insulator
b)Conductor
c) Semiconductor
3. What does the output voltage of an op-amp depend upon?
a) The resistors in the circuit
b)The op amp bandwidth
c) The gain of the op-amp
__________________
Homer not function well beer without !
Module 4 iv
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1. The cogging effect in synchros is rectified by
a) using carbon brushes
b)using an elliptical cog
c) skewing the rotor
2. A transistor is said to be in the quiescent state when
a) no signal is applied to the input
b)it is unbiased
c) no currents are flowing
3. In an unbiased p-n junction, current flow is
a) due to the diffusion of minority carriers only
b)zero, because no charges are crossing the junction
c) zero, because equal but opposite currents are crossing the
junction
4. Reversal of the power supply to either the transmitter or the
receiver of a torque synchro system would
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
5. Torque synchro systems are normally used when the
a) mechanical load is low
b)mechanical load is high
c) system accuracy is of extreme importance
6. 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
c) the base is common to the emitter and collector circuits
7. What device transfers one energy type to another?
a) Transmitter
b)Transducer
c) Transponder
8. Which way does conventional current flow in a PNP junction?
a) Collector to emitter
b)Emitter to base
c) Collector to base
9. Electrical power is supplied to a synchro rotor
a) directly
b)through slip rings
c) through a commutator
10. The purpose of a flywheel incorporated in a synchro is to
a) increase the driving force
b)prevent oscillations
c) prevent insect ingress
1. In an operational amplifier, the two input waves are the same
amplitude, same frequency, but exactly anti-phase. What would the output
be?
a) Double
b)Zero
c) Half
2. A thyristor has which of the following?
a) High resistance when switched on
b)High resistance when switched off
c) A positive temperature coefficient
3. On an integrated circuit the hole in the top left corner is pin 1.
The pins are counted
a) clockwise
b)anticlockwise
c) from left to right
4. With reference to the circuit shown below, how is the transistor
configured?
a) Common emitter
b)Common collector
c) Common base
5. In the circuit diagram above, R1 and R2 are used to
a) set the transistor gain
b)set the DC bias level
c) increase the base voltage
6. In a synchro system, if two stator lines are crossed the receiver
will
a) not be affected
b)be 180o out
c) reverse direction
7. In the following Boolean algebra statement, which gate is described?
F = A + B + C
a) Or
b)Not
c) And
8. In an E and I signal generator at datum, the voltage on the secondary
windings
a) are equal and opposite
b)is maximum
c) is zero
9. In a synchro resolver, the stator coils are at what angle in relation
to one another?
a) 45 degrees
b)80 degrees c) 90 degrees
10. In a synchrotel, the
a) rotor coil is fixed and the stator coil moves
b)rotor coil and stator coil is fixed
c) stator coil is fixed and the rotor coil moves
1. On a PCB, a decoupling capacitor is used to get rid of transient
currents between which points?
a) The electronic circuit and the aircraft ground
b)Interspaced along the circuit
c) The negative rail and the rest of the circuit
3. In an LED, what is used to make the colour?
a) The doping material
b)The electrons
c) The plastic lens cover
4. An atom with 5 electrons in its outer shell is part of
a) an N type material
b)a P type material
c) a C type material
5. In a FET, the junction connections are called
a) drain, source and gate
b)base, collector and emitter
c) drain, collector and junctions
6. In the Boolean algebra statement below, the gate described is
F = A.B.C
a) Nand
b)Nor
c) And
7. With a small amplitude voltage, what type of diode would you use to
produce the output waveform?
a) Shottky
b)Gunn
c) Zener
8. An increase in negative feedback to the servo amplifier
a) increases amplifier stability
b)decreases amplifier stability
c) has no effect
9. How is a push-pull transistor arrangement connected?
a) emitter to emitter
b)collector to collector
c) base to base
10. Thermal runaway in a transistor is caused by
a) excessive heat causing maximum current flow
b)excessive heat causing minimum current flow
c) low heat causing minimum current flow
1. A single integrated circuit Op Amp has how many pins?
a) 4
b)7
c) 8
2. What is the output of the amplifier shown below?
a) 0V
b)3V
c) 5V
3. A thyristor is commonly used for
a) voltage regulation
b)overvolts regulation
c) rectification
4. A diode which emits photons when conducting is a
a) zener
b)varactor
c) light emitting
5. Avalanche breakdown occurs when
a) forward bias becomes excessive
b)forward bias exceeds a certain value
c) reverse bias exceeds a certain value
6. The electrodes of an SCR are
a) anode, cathode, source
b)source, drain, gate
c) gate, cathode, anode
7. What gives an LED its colour?
a) A gas
b)The cover
c) Composition and impurity of the compound
8. For conduction of a transistor the emitter junction is
a) fwd biased
b)reverse biased
c) fwd or reverse as appropriate to the input signal
9. In a PNP transistor which way does conventional current flow
a) base to emitter
b)collector to emitter
c) emitter to collector
10. Infinite gain, infinite input impedance & zero output impedance is
characteristic of a
a) Class A amp
b)Class B amp
c) Op amp
1. Forward voltage of a silicon diode is
a) 0.6V
b)0.2V
c) 1.6V
2. An advantage of a common emitter is
a) it is a voltage follower
b)it has high power gain
c) it has high voltage gain
3. What amplifier is biased at cut off
a) A
b)B
c) C
4. When testing a transistor with an ohmmeter, what is the resistance of
the emitter/collector?
a) High resistance one way
b)High resistance both ways
c) Low resistance both ways
5. What is the typical volts drop across an LED
a) 1.6V
b)0.2V
c) 0.4V
6. What diode gives off light photons when forward biased
a) LED
b)Shottky diode
c) Gunn diode
7. A logic circuit with more than one gate will have
a) one of 2 states of logic output
b)2 or more outputs
c) an analogue output
9. In a synchro, what is used to convert signals from one form to
another?
a) Transmitter
b)Transducer
c) Transformer
10. Components on an integrated circuit are
a) in the solid
b)don't need them
c) on the surface
1. What diode is used to stop power spikes in a coil?
a) Two directional zener diode
b)Shottky diode
c) Gunn diode
2. The anode of a diode is connected to a +4v DC supply and the cathode
is connected to a +2v DC supply. The diode is
a) forward biased not conducting
b)reverse biased not conducting
c) forward biased conducting
3. Using electron flow in a diode the current flows from
a) Anode to Cathode
b)Cathode to Anode
c) Cathode to Base
4. A control surface position feedback signal is
a) proportional to surface position
b)inversely proportional to surface position
c) non-linear
5. In a PNP transistor, conventional current will flow when
a) the emitter is more positive than the base
b)the base is more positive than the emitter
c) the collector is more positive than the emitter
6. An E&I transformer out of datum has
a) equal and opposite voltages in each windings
b)unequal and opposite voltages in both windings
c) no voltage in either winding
7. A gyro will provide
a) rate feedback
b)velocity feedback
c) positional feedback
8. In a common collector circuit the output and input are
a) out of phase by 90o
b)in phase
c) out of phase by 60o
9. In velocity feedback the signal is
a) in phase
b)out of phase
c) equal to the error signal
10. 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
c) raises the potential barrier
__________________
Homer not function well beer without !
Module 4 iii
________________________________________
1. The junction barrier offers opposition to only
a) holes in the p-region
b)free electrons in the n-region
c) majority carriers in both regions
2. An increase in velocity feedback will
a) decrease the speed the load moves
b)increase the speed the load moves
c) have no effect on speed
3. A two phase motor will stop when
a) the reference phase is reversed
b)the control phase is reversed
c) the control phase is zero
4. A tachogenerator output is
a) variable frequency, constant voltage
b)variable voltage, constant frequency
c) variable frequency, variable voltage
5. Rate feedback can be obtained from a
a) synchro
b)tachogenerator
c) potentiometer
6. Positional feedback can be obtained from a
a) synchro
b)tachogenerator
c) potentiometer
7. The frictional force in a servomechanism that is proportional to
speed is called
a) stiction
b)coulomb friction
c) viscous friction
8. The 'null' point in a control synchro is when the two rotors are
a) at 90o to each other
b)parallel to each other
c) wired in series
9. If two of the stator leads are cross connected in a control synchro
system, a 25o clockwise rotation of the input rotor would result in the
output rotor
a) moving 25o clockwise
b)moving 25o anticlockwise
c) moving 180o to rectify the defect
10. Damping in a servomechanism is easier to apply if
a) the mechanism is light and has low inertia
b)the mechanism is heavy and has high inertia
c) the mechanism is light and has high inertia
1. Reverse bias
a) lowers the potential barrier
b)raises the potential barrier
c) greatly increases the majority carrier current
2. If the electrical connections to the feedback generator in a control
synchro system were disconnected, the
a) motor would run in the wrong direction
b)input signal to the amplifier would reduce
c) system would tend to oscillate
3. An increase in servo amplifier gain
a) reduces the speed of the system
b)increases system response
c) reduces tendency to hunt
4. In a control synchro the stator current ceases to flow when the
a) CT rotor is at null
b)two rotors are aligned
c) power is removed
5. The term 'velocity lag' refers to a
a) speed error
b)position error
c) acceleration error
6. The rotor of an AC tachogenerator
a) has skewed slots
b)has a copper, brass or aluminium cylinder
c) rotates at constant speed
7. A servo system with transient negative velocity feedback
a) is damped with little velocity lag
b)is damped with high velocity lag
c) is underdamped with high velocity lag
8. To reverse the direction of rotation of a two phase induction motor
a) reverse the polarity of the control phase
b)reverse the polarity of both the control phase and reference phase
c) shift the reference by 90o
9. In a rate servo (speed control) the signal into the servo amplifier
is
a) input voltage plus tachogenerator output
b)input voltage minus tachogenerator output
c) input voltage plus position feedback voltage
10. Loss of DC to a servo amplifier causes the motor to
a) run continuously
b)stop
c) reverse
1. Avalanche breakdown occurs when
a) forward current becomes excessive
b)forward bias exceeds a certain value
c) reverse bias exceeds a certain value
2. An AC servo demand can be converted to drive a DC motor by the
introduction of a
a) rectifier
b)modulator
c) demodulator
3. Synchro indicator systems are used when the indication is required to
move
a) a fraction of the input distance
b)slower than the input rate
c) at the same rate as the input
4. A linear variable differential transformer is used to measure
position feedback where
a) 360o of rotation and high angular accuracy is required
b)accuracy is of limited importance but robust construction and
reliability is important
c) an output whose phase is related to direction of movement and
amplitude linear over a wide range
5. A low frequency sinusoidal input will cause a closed loop
servomechanism load to
a) move to a demand position with no overshoot
b)move backwards and forwards at the input frequency
c) move to the demand position and then return to the datum position
without any overshoot
6. To reduce oscillations about a demand position
a) the amount of velocity feedback would be decreased
b)the amount of velocity feedback would be increased
c) the amount of position feedback would be increased
7. If a servo amplifier is suffering from drift
a) the load would move to a new position, proportional to the drift and
stay there
b)the load would move to a new position, proportional to the drift and
then return back to the datum position
c) the load would oscillate about the datum position
8. In a transient velocity feedback circuit, the tachogenerator output
is summated with the demand voltage
a) only when the load is slowing down
b)at all times when the load is moving
c) only when the load is speeding up or slowing down
9. Positive feedback applied to a servomechanism
a) decreases the response of the system
b)opposes the demand signal
c) increases the response of the system
10. A differential synchro rotor consists of
a) one winding parallel to the transmitter rotor
b)two windings at 90o apart
c) three windings at 120o apart
1. A differential synchro transmitter used for addition has
a) the TDX S1 and S3 connections cross connected to the TX
b)the TDX S1 and S3 connections cross connected to the TR
c) the TDX R1, R3 and S1, S3 connections cross connected to the TX
2. If forward bias is increased from zero on a p-n junction, a rapid
increase in current flow for a relatively small increase in voltage occurs
a) only after the forward bias exceeds the potential barrier
b)when the flow of minority carriers is sufficient to cause an avalanche
breakdown
c) when the depletion layer becomes larger than the space charge area
3. An LVDT has
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
4. 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
c) dissipate coil spikes on switch off
5. Differential transmitters are used to
a) add or subtract two electrical signals
b)add or subtract a mechanical signal to an electrical synchro signal
c) increase the operating speed of the synchro receiver
6. To convert a differential synchro from subtraction to addition you
would
a) reverse the reference phase supply
b)change over two rotor and stator connections
c) change over all three stator windings
8. 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
c) the inputs are two voltages
9. To check the forward resistance of a diode with a multimeter, the
lead connected to the positive terminal is put to the
a) anode
b)cathode
c) either anode or cathode
10. A resolver synchro output is obtained from a rotor with
a) one single coil
b)two coils at 90o to each other
c) three coils at 120o to each other
1. The input and output signals of a common emitter amplifier are
a) equal
b)out of phase
c) in phase
2. The output of a resolver synchro is
a) dependant upon the position of the rotor only
b)proportional to the speed of input rotation
c) a function of the rotor position and excitation voltage
3. The rotor of an autosyn position indicating system is
a) a permanent magnet
b)an electromagnet
c) spring controlled
4. A band pass filter excludes frequencies
a) above the frequency required only
b)below the frequency required only
c) above and below the frequency required
5. The rotor of a magnesyn transmitter is
a) a dc electromagnet
b)a permanent magnet
c) an ac electromagnet
6. In general the accuracy of a synchro system increases if the
a) stator current is high
b)stator current is low
c) rotor current is high
7. Torque synchro systems are normally used when the
a) mechanical load is low
b)mechanical load is high
c) system accuracy is of extreme importance
8. In a resolver synchro the stator windings are electrically disposed
by
a) 90o
b)120o
c) 180o
9. The induced signal in the output coils of the magnesyn system
a) de-saturates the soft iron core
b)damps the pointer oscillations
c) is of a value of 800 Hz
10. 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
c) is in the opposite direction to the primary field
Module 4 ii
________________________________________
8. Mechanical friction in a servo results in
a) reduced gain
b)increased damping
c) increased inertia
9. The position feedback signal is
a) in phase with the input demand signal
b)in anti-phase with the demand signal
c) phase advanced by 90o with respect to the input signal
10. A servo system that overshoots and oscillates is
a) under damped
b)over damped
c) critically damped
1. The power supply to a torque synchro system is connected to
a) the transmitter stator
b)the transmitter rotor only
c) the transmitter and receiver rotors
2. If the rotor of the receiver in a torque synchro system was prevented
from aligning with the transmitter rotor, then
a) the transmitter rotor will turn to align with the receiver rotor
b)the receiver will overheat
c) a high current will flow in the stator windings
4. A zener diode
a) stabilizes voltage at a predetermined level
b)allows current to flow in one direction
c) acts like a switch
5. The common collector amplifier is sometimes called the emitter
follower circuit because
a) the emitter current follows the collector current
b)the emitter voltage follows the base voltage
c) the emitter voltage follows the collector voltage
6. In a toroidal resistance transmitter indicator system, the power
supply is connected to
a) the brushes
b)the resistor slab
c) the rotor
7. When a servo has reached its null and stopped, the velocity feedback
is
a) zero
b)maximum and anti-phase
c) maximum and in phase
8. The primary purpose of rate feedback in a positional servo system is
to
a) ensure minimum response time
b)prevent excessive overshoot
c) ensure system linearity
9. In an AC rate servo, a steady input will result in the servomotor
a) oscillating about a new datum
b)rotating at a constant speed
c) rotating to a new datum position
10. An E&I bar output at datum has
a) no induced voltage in the secondary windings
b)an imbalance of voltages in the secondary windings
c) equal and opposite voltages induced in the secondary
1. A non-inverting op-amp
a) has a non-inverting input and an inverting output
b)has an inverting input and a non-inverting output
c) a non-inverting input connection only
2. Amplifiers may be classified as
a) common emitter or common collector amplifiers
b)voltage amplifiers or impedance amplifiers
c) voltage amplifiers or power amplifiers
3. What is a shottky diode used for?
a) Very high frequency applications
b)Stabilsation
c) Rectification
4. The result of cross connecting two of the transmission leads in a
torque synchro system and then turning the rotor of the transmitter 60o
clockwise would be
a) the receiver would move 60o clockwise
b)the receiver would move 120o anticlockwise
c) the receiver would move 60o anticlockwise
5. The control windings of a two phase servomotor is supplied with AC
voltage of
a) constant amplitude
b)variable phase
c) variable amplitude, variable phase
6. In a torque synchro that includes a differential synchro the power
supply is connected to
a) the transmitter rotor only
b)the transmitter and receiver rotors only
c) all three rotors
7. A differential synchro rotor has
a) three windings
b)two windings
c) one winding
8. If the rotor of a control synchro sticks
a) the system hunts
b)high current will flow
c) the position feedback will oscillate
9. With the reversal of the connections to the rotor of the transmitter
of a torque synchro, the position of the receiver rotor will be
a) unchanged
b)changed by 120o
c) changed by 180o
10. The application of a 'stick-off' voltage to a control synchro servo
system is
a) to overcome the effect of static friction
b)to overcome the effect of viscous friction
c) to prevent alignment to a false null
1. When removing a microprocessor
a) no damage is done by static discharge
b)considerable damage can be done by static discharge
c) ensure the power is OFF to avoid static discharge
2. An amplifier can provide both voltage gain and current gain when it
is connected in the
a) common base configuration
b)common emitter configuration
c) common collector configuration
3. How do you increase voltage gain of an amplifier?
a) decrease base circuit bias
b)decrease input resistance
c) increase input resistance
4. In a resolver synchro the stator windings are electrically displaced
by
a) 90o
b)120o
c) 180o
5. A servo system may include a brake, an automatic trim system is one
example where a brake is used. The brake is
a) applied during trimming to prevent oscillations about the demand
position
b)applied when trimming is complete to prevent stabilizer creep
c) applied during trimming to prevent servo runaway
6. A resolver synchro output is obtained from a rotor with
a) one single coil
b)three coils at 120o
c) two coils at 90o
7. 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
c) when power is removed
8. 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
c) to make it run at constant speed
9. 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
c) is changed by 180o
10. The rotor of a torque synchro indicator is
a) supplied with an excitation voltage
b)short circuited
c) connected in series with the transmitter stator coil
1. 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
c) raises the potential barrier
2. How are the pins numbered on an op-amp IC?
a) counter clockwise from the dot
b)clockwise from the dot
c) from left to right from the dot
3. To increase the output of a servo amplifier, it is necessary to
a) reduce the tacho feedback
b)increase the tacho feedback
c) increase the position feedback
4. Angular displacement of the control coils with respect to the
reference coils in a two phase induction motor are
a) 0o, 180o
b)90o, 270o
c) 90o, 120o
5. a two phase induction motor used in a servomechanism
a) will always require a starter
b)is self starting under light loads
c) runs with no slip
6. A servomotor having only a tachogenerator as a feedback device will
a) vary its speed with input error voltage
b)have a constant speed for any given input voltage
c) null out at a position dependant upon input error voltage
7. A hysteresis servo motor is used in a servomechanism because
a) it has good starting characteristics
b)good speed/voltage relationship
c) low inertia
8. The null position of a torque synchro system is when
a) the TX and TR rotors are parallel to each other
b)the TX and TR rotors are 90o to each other
c) the TX and TR rotors are 120o to each other
9. Reversal of two of the stator connections on a torque synchro
receiver would cause
a) the transmitter to become the receiver
b)the output to move the same direction as the input
c) the output to move the reverse direction to the input
10. An AC tachogenerator stator has
a) two windings 180o apart
b)three windings 120o apart
c) two windings 90o apart
1. A junction diode
a) has one p-n junction
b)is similar to a vacuum diode but cannot rectify
c) can handle only very small currents
2. When the rotor of an AC tachogenerator is stationary, the rotor has
a) no circulating currents
b)low circulating currents
c) no magnetic fields
3. The output of a tachogenerator should be
a) sinusoidal
b)exponential
c) linear
4. With a constant input to a speed control servo, the servo motor
a) moves to a certain position
b)moves at a constant speed
c) oscillates, but otherwise does not move
5. A closed loop servomechanism
a) must only have position feedback
b)must have both position and velocity feedback
c) can have either position or velocity feedback
6. Critical damping in a servomechanism is
a) the point which allows just one overshoot before the load comes to
rest
b)the amount of damping that results in the load just not oscillating
c) the critical damping required for the optimum damping of the
servomechanism
7. In a control synchro system the power supply is connected to the
a) transmitter rotor and amplifier
b)receiver rotor and amplifier
c) transmitter and receiver rotors
8. Reverse rotation of a control transformer rotor can be caused by
a) connections between the transformer rotor and the amplifier reversed
b)connections to the transmitter rotor reversed
c) short circuit between two transmission lines
9. Velocity feedback
a) opposes the demand input
b)assists the demand input
c) prevents dead space errors
10. Velocity lag can be decreased by
a) introduction of an integrator
b)keeping the error detector (summing point) output as low as possible
c) decreasing the coulomb friction in the system
Module 4 i
________________________________________
1. What gives the colour of an LED?
a) The plastic it is encased in
b)The active element
c) The type of gas used inside it
2. A germanium diode is used for
a) rectification
b)voltage stabilization
c) modulation
3. Why is a diode put in parallel with an LED?
a) To protect it from AC
b)So it will work only above a certain voltage
c) So it will work only below a certain voltage
4. When testing the forward bias of a diode with a multimeter
a) the positive lead of the ohmeter is placed on the cathode
b)the positive lead of the ohmeter is placed on the anode
c) it does not matter which terminal the positive lead of the ohmeter
is placed
5. In an NPN transistor the P is the
a) collector
b)base
c) emitter
6. The output of a tachogenerator is
a) proportional to speed of rotation
b)proportional to position
c) proportional to acceleration
7. AC power is supplied to
a) torque receiver only
b)torque transmitter only
c) both the torque receiver and torque transmitter
9. How is a PCB protected after manufacture?
a) With non-conductive varnish
b)With wax
c) By conformal coating
10. A differential synchro
a) can only be used as a transmitter
b)can only be used as a receiver
c) can be used as either a transmitter or a receiver
1. Which of the following describes the characteristics of a Thyristor?
a) High voltage handling
b)High current handling
c) High power handling
2. A semiconductor doped with an element having a valency of 5 will
produce
a) an N type material
b)a P type material
c) either an N type or a P type depending on what type of
semiconductor material is used
3. What are the ideal characteristics of an Op Amp?
a) Infinite gain, infinite input Impedance and infinite output
impedance
b)Low gain, infinite input Impedance and zero output impedance
c) Infinite gain, infinite input Impedance and zero output impedance
5. What gate does the following Boolean expression represent
F = A.B.C
a) AND
b)OR
c) NOT
6. What gate does the following Boolean expression represent
F = A+B+C
a) NOT
b)NOR
c) OR
7. To decrease the voltage gain of a common emitter amplifier you
would increase the resistance in the
a) base circuit
b)collector circuit
c) emitter circuit
8. A resolver has
a) 2 coils on the rotor and 2 coils on the stator
b)3 coils on the rotor and 2 coils on the stator
c) 2 coils on the rotor and 3 coils on the stator
9. The 'null' point on a control synchro is when the two rotors are
a) at 90o to each other
b)parallel to each other
c) wired in series
10. A FET when compared to a junction transistor is
a) low impedance
b)high impedance
c) current operated
1. What type of diode would be used to stop voltage spikes across a coil
of a relay?
a) Gunn diode
b)Schottky diode
c) Double acting diode
2. A silicon diode, when compared to a germanium diode has
a) a higher forward bias voltage
b)less forward bias voltage
c) the same forward bias voltage
3. A zener diode is used for
a) rectification
b)voltage stabilization
c) modulation
4. A multi-layer PCB has
a) one layer on either side
b)two or more layers on one or both sides
c) two or more layers connected in series
5. When a servomotor overshoots after a step input and oscillates it is
a) over damped
b)under damped
c) critically damped
6. The rotor of a desynn indicator is
a) an electromagnet
b)a permanent magnet
c) an AC magnet
7. The position feedback from a potentiometer is
a) anti-phase
b)in phase
c) 90 degrees out of phase
8. A differential synchro has
a) 3 phase stator, 3 phase rotor
b)single phase stator, 2 phase rotor
c) 3 phase stator, single phase rotor
9. When a servomotor has stopped, the rate feedback from a
tachogenerator is
a) zero
b)maximum and in phase
c) maximum and anti-phase
10. A tachogenerator is usually used for
a) rate feedback
b)angular feedback
c) position feedback
2. Differential synchros have
a) a transmitter only
b)a receiver only
c) a transmitter and a receiver
3. In an integrated circuit, the components are mounted
a) by means of wires connecting them
b)by metal oxide film
c) by metal screws
5. One characteristic of the emitter follower is
a) low resistance output
b)low current amplification
c) high voltage amplification
6. A reduction from the optimum setting of the velocity feedback in a
servo loop could cause
a) low servo gain
b)instability
c) slow response
7. In a torque synchro system, the power supply is connected to
a) the rotor windings of the transmitter only
b)the rotor windings of both the transmitter and receiver
c) the stator windings of the transmitter
8. The phase difference between the supplies of a two phase induction
motor is
a) 180o
b)90o
c) 0o
9. To reduce overshoot errors in a synchro
a) the system will have position feedback
b)the system will have velocity feedback
c) the gain of the amplifier is increased
10. A synchro transformer is used to
a) derive an error voltage from a synchro transmitter signal and a
shaft position
b)obtain a 26 volt AC reference
c) add the output of two synchro transmitters
2. Reversal of the complete power to a torque synchro system will
a) have no effect
b)cause reverse rotation of the receiver rotor
c) displace the receiver rotor by 180o
3. The power supply to a torque synchro system is
a) AC
b)DC
c) AC or DC
5. When a positive voltage is applied to the base of a normally biased
n-p-n common emitter amplifier
a) the emitter current decreases
b)the collector voltage goes less positive
c) the base current decreases
6. An amplifier current gain will be slightly less than 1, but its
voltage gain will be high, if it is connected in the
a) common base configuration
b)common emitter configuration
c) common collector configuration
7. An open loop system is one which has
a) no direct feedback loop
b)rate feedback loop
c) position feedback only
Electrics
________________________________________
The DC generator main contactor is welded closed. The fault indicated is
a The generator failure warning light illuminates
b The generator ammeter reading is high
c# The aircraft generator continues to rotate after the engine is shut down
The DC generator switch directly controls the
a Generator field
b# Generator contactor
c Generator warning light
Increasing the load on a permanent magnet generator will
a Reduce the terminal voltage by a large amount
b# Reduce the terminal voltage by a small amount
c Increase the terminal voltage by a small amount
The separately excited generator voltage is
a Independent of rotational speed
b Controlled by the load
c# Controlled by the separate supply
The series wound generators terminal voltage will, when below saturation
a# Increase with an increase in load
b Decrease with an increase in load
c Decrease with a decrease in rotational speed
The shunt wound generator is normally started
a# Off load
b On load
c Either of the above
The shunt wound generator is controlled by a variable resistance in
a Series with the armature
b# Series with the field
c Parallel with the armature
In a cumulative compound wound generator the
a The series and shunt fields oppose each other
b# The series and shunt fields assist each other
c Voltage falls suddenly with an increase in load
Which generators are usually used on aircraft
a Series
b# Shunt
c Compound
Increasing the speed of an aircraft generator results in an automatic
a# Field circuit resistance increase
b Field circuit resistance decrease
c Armature circuit resistance increase
In the shunt generator the field is supplied by
a A separate supply
b# The armature
c The load
The shunt generators voltage falls on load due to the
a High resistance of the field
b Low resistance of the armature
c# Armature volts drop
Which one of the following aircraft cables if heated excessively could give off toxic fumes
a Nyvin
b Tersil
c# Efglas
Which of the following cables is most flexible throughout its temperature range
a# Efglas
b Unifire F
c Tersil
Which of the following cables has a conductor of tinned copper strands
a# Nyvin
b Tersil
c Efglas
A cable is marked Tersil 22 the 22 refers to
a The current rating
b# The American wire gauge of the conductor
c The current/weight ratio
To measure current in a circuit the ammeter is connected
a In parallel with the load
b# In series with the load
c Across the power supply
The resistance of an ammeter must be
a High to create a large volts drop across it
b Low because the ammeter is in parallel with the circuit
c# Low to prevent volts drop across it
A volt meter may be used in a circuit to measure
a EMF of the supply only
b Volts drop across loads only
c# Both of the above
To measure voltage in a circuit a voltmeter is connected
a In series
b# In parallel
c Only across the power supply
The resistance of a voltmeter must be
a Low to provide a parallel path for the circuit current
b# High so that little current passes through it
c Low to prevent overloading the circuit
The forces acting on a meter which moves the pointer over the scale is called
a The controlling force
b The turning force
c# The deflecting force
The force acting on a meter which returns the pointer to zero is called the
a# The controlling force
b The turning force
c The deflecting force
The force acting on a meter which opposes the deflecting force is called the
a# The controlling force
b The turning force
c The damping force
The damping force in a meter operates
a Only when the pointer is stationary
b# Only when the pointer is moving
c At all times whether the pointer is moving or stationary
The damping force
a# Prevents oscillation of the pointer
b Assists the pointer to move over the scale
c Returns the pointer to zero
In a moving coil meter the deflecting force is provided by
a Hairsprings which move the pointer towards full scale
b A soft iron permanent magnet
c# A current carrying coil pivoted in a permanent magnet field
In a moving coil meter the deflecting force
a Decreases with an increase of current through the coil
b Increases with a decrease of current through the coil
c# Increases with an increase of current in the coil
The controlling force in a moving coil meter is afforded by
a Single hairspring only
b Taut bands only
c# Either hairsprings or taut bands
Hairsprings in a moving coil meter provide
a# A controlling force and a method of electrical connections to the coil
b The deflecting and damping force
c Electrical connections to the coil only
In a moving coil meter
a The hair springs are permanently attached at both ends
b# The outer end of one spring is movable to provide zero adjustment
c The hairsprings are movable at both ends to provide full scale and zero adjustments
In a moving coil meter damping is provided by
a# Electromagnetic induction in the coil frame
b An air or oil dashpot
c By a system of levers
When using a moving coil meter to measure current, as an ammeter it is usual to
a Connect a very high resistor in parallel with the coil
b# Connect a very low resistor in parallel with the coil
c Connect a very high resistor in series with the coil
The resistor used to extend the range of an ammeter is called a
a Variac
b# Shunt
c Multiplier
A moving coil ammeter has a FSD current of 1mA and a resistance of 0.1k. The value of resistor required to extend the range of a meter to read 100mA is
a# 1 ohm approx.
b 99 ohm approx.
c 100 ohm approx.
An external resistor used to extend the range of an ammeter usually has
a Two connections only
b Two voltage connections and one voltage connections
c# Four connections two for the meter and two for the external circuit
An external resistor used to extend the range of an ammeter will be marked with
a The value of the resistor in ohms
b# Fullscale current and millivolts drop
c Fullscale current and its value in ohms
A moving coil meter with a coil resistance of 100 ohms and a FSD current of 1mA will when used as a voltmeter measure voltages from
a# 0-100mV
b 0-1V
c 0-100v
The resistor used to extend the range of a moving coil voltmeter is called a
a Variac
b Shunt
c# Multiplier
The resistor used to extend the range of a moving coil voltmeter is placed
a In parallel with the coil
b In series with the load
c# In series with the coil
A 100mv voltmeter having a FSD current of 1mA and a coil resistance of 100 ohms. The value of resistance required to extend its range to 0-10V is
a 990 ohms
b# 9900 ohms
c 9990 ohms
The differential cutout contacts are closed using the
a# Voltage coil only
b Current coil only
c Both voltage and current coils
The indication of a short circuit in the remote ammeter shunt is that the
a Generator fails to come online
b Generator failure warning light remains on
c# Generator operates normally but the ammeter reads zero
With a rising generator voltage in a DC generation system the
a# Undervolts relay closes before the differential relay
b Differential relay closes before the undervolts relay
c Undervolts and differential relays operate independently
1. Inductance in a circuit smoothes the: - Current.
2. An Increase in frequency in an inductive circuit will result in:
A decrease in current flow.
3. The symbol X means total:
Reactance.
4. Two Equal voltages out of phase by 180 degrees would equal:
Zero.
5. At Resonance in an RCL circuit, total impedance equals total:
Reactance.
6. The Voltage vectors for a series resonant circuit are:
One single vector
7. In an Inductance at saturation, the impedance is :
Zero.
8. A gas filled valve is recognised in a circuit diagram by a:
Black dot inside the symbol.
9. The RMS value of a sine wave is :
0.707 x max value
10. An auto transformer has :
One winding.
11. In an AC circuit, apparent power is calculated from :
VI
12. The flux density in a B/H curve is represented by the :
B value.
13. Two in phase voltages may be represented by :
Vector sums.
14 Circuit power factor may be found by ;
True power over apparent power.
15. A lagging power factor may be improved by:
Increasing the capacitance.
16. In an isolating transformer, if the secondary current is increased the primary current will :
Increase.
17. To measure current in a circuit, how is the ammeter connected?
In series with the load.
18. What does a voltmeter measure?
Both supply voltages and volts drops across the circuit.
19. What is the resistance of an ammeter?
Low to prevent a large volts drop across it.
20. How is a voltmeter connected?
In parallel.
21. What is the resistance of a voltmeter?
High, so little current passes through it.
22. What is the force acting on a meter, which moves the pointer over a scale?
Deflecting force
23. What force returns the pointer to zero?
Controlling force.
24. What force in a meter opposes the deflecting force?
Controlling force.
25. When does the damping force in a meter operate?
Only when the pointer is moving.
26. What does the damping force do?
Prevents oscillation of the pointer.
27. In a moving coil meter, what is the deflecting force provided by?
A current carrying coil pivoted in a permanent magnetic field.
28. In a moving coil meter, what does the deflecting force do?
Increases, with an increase in current through the coil.
29. In a moving coil meter, the deflecting force is :
Greatest when the indicator reads full scale.
30. The controlling force in a moving-coil meter is provided by:
Either hairsprings or taught bands.
31. What do hairsprings in a moving-coil meter provide?
A controlling force and method of electrical.
32. In a moving coil meter, which is true?
The outer end of one spring is movable to provide a zero adjustment.
33. The hairspring in a moving-coil meter:
Provides a zero torque when the pointer is at zero.
34. In a taught band moving-coil meter, the bands provide?
A controlling force, and a method of electrical connection to the coil.
35. How is mechanical zero in taut band moving-coil meters achieved?
Twisting one of the fixed mounts of the bands.
36. In a moving-coil meter, how is damping provided?
Electro magnetic induction of the coil frame.
37. When using a moving-coil meter to measure current, how can larger currents be measured?
By connection a very low resistor in parallel with the coil.
38. What is the resistor used to extend the range of an ammeter called?
A shunt.
39. A moving-coil meter has an FSD current of 1 mA and a coil resistance of 100 ohms, what value resistor would be used to extend the range to read 100 mA?
1 ohm (approx.)
40. An external resistor used to extend the ammeter range usually has:
Four connections, two for the meter and two for external circuit.
41. An external resistor used to extend the ammeter range will be marked with:
Full-scale current and millivolts drop.
42. Damping is normally achieved by?
Eddy currents in the coil and coil former.
43. A MCM with a coil resistance of 100 ohms and a FSD current of 1mA, will when used as a voltmeter measure?
0-100mV
44. What is the resistor used to extend the range of a moving coil voltmeter called?
Multiplier.
45. How is a resistor used to extend the range of a moving coil voltmeter connected?
In series with the coil.
46. A 100 millivolts voltmeter having a FSD current of 1mA and a coil resistance of 100 ohms, what is the value of the resistance required to extend its range to 0-10V?
9900 ohms
47. A voltmeter with a low ohm per volt rating will do which of the following?
Indicate a value lower than the actual volts drop being measured.
48. How is the ohm per volt rating of a voltmeter calculated?
By dividing the FSD current into one Volt.
49. When using a MCM to measure ac which of the following is correct?
A rectifier must be used to change the ac to dc.
50. When using a MCM to measure ac values:
The meter measures average values but is scaled to read RMS
51. To extend the range of an ac MC voltmeter :
Step up/down transformers may be used.
52. What does a thermo-junction meter consist of?
A MCM and a thermo-couple.
53. A thermo-junction meter may be used to measure?
ac or dc.
54. What is a thermo-couple?
A junction of two different metals which when heated produces an emf.
55. A thermo-junction meter when used to measure ac :
Measures and indicates rms values.
56. The scale on a thermo-couple meter is?
Square law.
57. How is damping in a moving-iron meter usually carried out?
Air dashpot.
58. A MIM may be used to measure?
ac and dc.
59. How is the deflecting force of a MIM provided?
Electromagnetic induction.
60. How is the controlling force acting in a MIM provided?
Hair spring.
61. How may the scale of a MIM be made almost linear?
By shaping the iron pieces.
62. When using a tong test ammeter:
The circuit need not be broken.
63. An electrostatic voltmeter may be used for?
ac or dc.
64. An electrostatic voltmeter has?
Low loading effect on a circuit.
65. A simple ohmmeter may be used to?
Measure continuity and unknown resistance values.
66. Before using a simple ohmmeter?
The test leads should be shorted together and the indicator set to zero.
67. The internal circuit of a simple ohmmeter consists of?
A moving coil meter in series with a battery and a variable resistor.
68. Test meters designed to check insulation resistances are often called?
Meggers.
69. Very low resistance measurements such as metal to metal are made with?
Bonding testers.
70. A ratiometer movement is used in?
Meggers and bonding testers.
71. What provides the deflecting force in ratiometer movements?
A current carrying coil in a permanent magnetic field.
72. What provides the damping force in ratiometer movement?
Eddy currents in the coils and formers.
73. The voltage out put of a megger used on aircraft is?
250V.
74. What is the voltage output of a safety ohmmeter?
Max 30V but regulated by the current flowing.
75. What is the out put voltage of a 500V megger?
Dependant on rotation speed of handle.
76. What is the scale reading on a 500V megger?
Non-linear from zero to infinity.
77. What does a 500V megger consist of?
A hand cranked generator and a ratiometer movement.
78. The cranking handle should be turned at what speed?
160 rpm.
79. The out put voltage of a 250v megger is?
Limited to 250V above 160 rpm
80. What is the scale reading on a 250V megger?
Non-linear from zero to infinity.
81. A 250V megger consists of a hand cranked generator and?
A ratiometer movement, smoothing circuit and voltage limiting circuit.
82. What is the purpose of the silicon-carbide disc in the 250V megger?
To act as a voltage regulator.
83. Safety ohmmeters are used on circuits under which conditions?
The testing current must not exceed a specified value.
84. What are typical values for maximum voltage and current in safety ohmmeters?
30V and 10 mA.
85. The armature winding in a safety ohmmeter is?
High resistance.
86. What does a bonding tester do?
Measures resistance values from 0 to 0.1 ohms.
87. Where does a bonding tester get its power from?
Internal NiCad cell.
88. Frequency meters a generally designed to measure?
A small range of frequencies.
89. What is the purpose of an oscilloscope?
To measure waveform and voltage.
90. What part of an oscilloscope gives visual display?
A CRT.
91. What is the maximum resistance between the main earth system and earthing device?
10 megohms.
92. What is the primary purpose of bonding metallic parts on an aircraft?
To prevent high potential differences building up between metallic parts.
93. Why does a primary bonding connection have a large cross-sectional area?
To maintain the same potential through out.
94. In what order do you carry out the three main electrical checks?
Bonding, Continuity, Insulation.
95. What is the minimum recommended bonding resistance between extremities of an airplane?
0.05 ohm.
96. When an engine is not in direct contact with its mounting, how should it be bonded?
With at least two primary conductors, one each side of the engine.
97. When carrying out a pre use check on a bonding tester, shorting the three prongs on both probes?
Should give a zero reading.
98. When an earth-return terminal assy. has been replaced, what checks required?
Bonding and milli-volts drop tests.
99. If a bonding testers leads are damaged, what must you do?
The leads and tester must be returned to the manufacturer, for repair and re-calibration.
100. When carrying out a bonding test on a current carrying earth terminal, what should the recommended resistance not exceed?
0.025 ohm.
101. When carrying out a milli-volts drop check, what is the approximate guide for a correct reading?
5 milli-volts drop for every 10 amps flowing.
102. When refuelling an aircraft why must the aircraft and tanker be bonded together?
To maintain both at the same electrical potential.
103. When carrying out a continuity test on a circuit where a known resistance exists, what instrument would you use?
A multi meter
104. Effective continuity is not possible unless?
The portion of the circuit under test must constitute a simple series circuit, with no parallel paths.
105. Why is a low voltage supply used for continuity testing?
To avoid breaking down any high resistance films that might exist between contacting surfaces.
106. If an insulation resistance tester is operated with the leads suspended in free air, what will the meter read?
Infinity.
107. When replacing a bonding connection and the original cannot be matched, what would you use?
One manufactured from the same type of material, but of greater cross section area.
108. How do we reduce or remove electrostatic charges on fibre glass surfaces?
The surface is treated with special conductive paint.
109. If bridging strips or bonding cords are fractured, what action?
Repalcement.
110. How is the accuracy of a bonding tester checked?
Use it to measure the resistance of three standard test resistors.
111. An insulation test is carried out on a group of cables, and a low reading obtained, what action?
Break down the circuit and carry out further checks.
112. What is a typical minimum insulation resistance value for an U/C bay?
2 megohms.
113. Whenever possible, a functional test should be carried out on an A/C using?
An external supply.
114. Immediately after carrying out an insulation check what should you do?
Note the readings and atmospheric conditions, and compare to previous reports.
115. How is an AVO zeroed on the ohms range?
By using the variable resistor.
116. A device that converts a physical quantity into a corresponding electrical signal is called?
A Transducer
117. Electrons in an atom orbit the nucleus in shells, the one nearest the nucleus is called?
K shell.
118. The maximum number of electrons this shell can contain is?
2 electrons.
119. These orbits taken by electrons are energy levels. An electron in the K shell will have?
Less energy then the L, M, N shells.
120. The unit used for energy level is?
The ampere hour.
121. For an electron to move from one level to another, there must be?
A vacant position into which it can move.
122. The highest occupied shell of and atom is called its ?
Valence shell.
123. Materials that behave as insulents at very low temperature, and conductors at high temperatures are called?
Intrinsic semiconductors.
124. When electrons are shared by atoms they form?
Covalent bonds.
125. Materials such as germanium and silicon where four covalent bonds are formed, are called?
Tetravalent elements.
126. Adding a small amount of impurity element to a crystal of intrinsic semiconductor material, is called?
Doping.
127. An N-type intrinsic semiconductor is?
Electrically neutral.
128. An N-type intrinsic semiconductor has been doped with?
A donor impurity.
129. Positive holes are created by doping an intrinsic semiconductor with?
A trivalent impurity.
130. In N-type materials the majority carriers are?
Electrons.
131. In P-type material the minority carriers are?
Elecrons.
132. A method to determine whether the majority carriers are holes or electrons in a semiconductor is to make use of?
The Hall effect.
133. In a P-N junction the area around the junction is know as?
The depletion layer.
134. The usual method of making connections to semiconductor devices is by?
ohmic contacts.
135. In a junction diode the depletion layer will disappear if the?
Junction is fwd biased.
136. When a junction diode is reversed baised, any current flow will be due to?
Minority carriers.
137. Diodes that are designed to operate in a reverse bias direction are known as?
Zener diodes.
138. A transistor is a semiconductor that can be used for?
Amplification.
139. The regions of a transistor are called?
The base, collector and emitter.
140. In order to achieve emitter-collector current, the base-emitter junction must be?
Forward-biased.
141. The initials FET stand for?
Field Effect Transistor.
142. In FET's the regions are designated?
The source, Drain and Gate.
143. Current flow in an FET is controlled by?
Gate voltage.
144. An FET operating in depletion mode will, if the source and drain are connected to the supply?
Will be normalyconducting???
145.An FET operating in the enhancement mode, will if connected to the supply be?
Not normally conducting.
146.A silicon controlled rectifier (SCR) is a type of?
Thyristor.
147.A triac can be used?
Only on ac circuits.
148. In a uni junction transistor, if the emitter junction is reverse biased , it acts as?
A simple potential divider.
1. An increase in plate area will increase battery?
Capacity
2. If the SG in one cell of a 24V Lead battery is low?
That cell is U/S
3. If the insulation resistance of a lead battery is down, it indicates?
Case Leakage
4. Temperature correction of the SG reading of a lead battery is?
+0.001 for 2.5F
5. The actual capacity of a battery can be obtained by?
The rate of discharge graph
6. A capacity test is required every?
3 months
7. The life of an aircraft battery is?
Until it fails the capacity test.
8. The capacity of a battery would maintain electrical services for a minimum of?
30 Mins.
9. Battery connections should?
Be smeared with petroleum jelly
10. If two 12V 40AH batteries are connected in series, the capacity would be?
24V 40AH
11. If a Lead acid battery is stored longer than 2 weeks it will require?
A freshening charge.
12. The nominal voltage for a lead cell is?
2V.
13. The electrolyte in a NICAD is?
Potassium Hydroxide.
14. The SG of the electrolyte in a nicad cell on discharge?
Stays constant.
15. Nicads are topped up?
At the end of a charging cycle
16. To determine the state of charge of a nicad battery?
A measured discharge test must be carried out.
17. Spilled nicad elecrolyte is neutralised by?
Boric acid
18. The plate materials in a fully charged nicad cell are?
Negative plate cadmium, positive plate nickel hydroxide.
19. The expected spring tension on the brushes of a 6 kw dc geny would be?
32 ozs.
20. Excessive brush sparking is caused by?
Low brush spring pressure.
21. The windings embedded in the pole faces of a geny are?
Compensating coils.
22. An indication of good commutation on a dc machine would be?
Little or no sparking at the commutator.
23. A dc machine is cleaned using?
Trice on the windings.
24. The bedding of brushes on dc apparatus?
Must never be done on the aircraft.
25. The voltage regulator on a singled engined aircraft can?
Be trimmed for voltage only.
26. Load sharing on a dc generation system is achieved by?
Circulating currents affecting the carbon pile for voltage trimming.
27. If compound dc generators are operated in parallel, they must?
Have an equalising or load sharing loop.
28. During regulation and load sharing checks, the genys output voltage is determined using?
29. Dc load share adjustment is carried out with?
All genys on line on load
30. After overhaul of a dc machine, and insulation check must be carried out when?
After function check while the machine is still warm.
31. The insulation/resistance of a dc motor would be?
Lower than the supply lines.
32. An actuator is an elecro-mechanical device comprising?
Split field, series windings,a brake, internal limit switches.
33. While an actuator is travelling, the position of the limit switches are?
Both open and closed are closed
34. if an actuator brake coil is open circuit, the actuator will?
Stop.
35. A suppressor in a dc geny is used to suppress?
Radio interference.
36. An open circuit on a lap machine would cause excessive?
Sparking
37. The expected rpm of a dc geny would be?
6000 rpm
38. With a voltage regulator in situ you can?
Adjust voltage trimming.
39. The equalising coil in a carbon pile regulator?
Is connected in series with the carbon pile
40. The ballast resistor in a carbon pile regulator is used to?
Stabilise the action of the regulator.
41. When making in- situ adjustments to a carbon pile regulator the?
Adjustments are made when the pile is warm
42. A pilot relay and a differential relay are incorporated in a dc geny control circuit?
The pilot operates before the differential relay.
43. The differential cut out contains a?
Differential and series coil.
44. The RCCO will operate ?
After the differential relay.
45. When a dc generator fails, the pilot will receive the following indications?
Zero current on the ammeter, and a red PFWL.
46. The PFWL will come on when the contacts of the?
Over volts relay opens.
47. The purpose of field flashing is to?
Change the polarity of residual magnetism in the field winding.
48. An over voltage is sensed by the?
The voltage sensing coil connected across the geny output.
49. The output stage of the voltage regulator for a dc generator is a power transistor. It acts as?
A switch.
50. The Tirill regulator is adjusted by?
Varying the spring tension.
51. Stabalising winding?
Oppose the voltage coil when transients occur.
52. Heave duty cable runs can be reduced by using?
Heavy duty relays.
53. Economy coils are?
To allow a relay to be held on with a low current.
54. AC relays?
Have laminated armatures.
55. Slugged relays?
Introduce a time delay in to circuit switching.
56. A milli-volts drop test is carried out on a heavy duty contactor with the contacts?
Closed
57. In a fuse HRC means?
High rupture capacity.
58. The current rating of a fuse indicates?
Current that can be carried without the fuse operating.
59. In an overload condition with a limiter in the circuit, the limiter would?
Allow the circuit to operate at over load for a short time.
60. An aircraft should carry at least the following amount of spare fuses?
10% or 3..which ever is the greater.
61. A trip free cb can be expected to trip in under a minuet with a load of at least?
1.5 the rated value.
62. A trip free cb?
Cannot be reset while the fault exists.
63. When the wite collar on a push pull cb is in view this indicates?
The cb is tripped
64. During a milli-volt drop test, the milli-voltmeter reads 150mV at 300A. Contact resistance is therefore?
0.0005
65. If the aircraft generators are operating, ground power must?
Not be paralleled with the generators.
66. The small pin on the external power plug?
Provides the hold in supply for the ground power contactor.
67. When the battery contactor is closed, the aircraft volt meter will read?
24v.
68. The resetting type fire detector depends for operation upon the?
Co-efficient of expansion of a steel tube.
69. The least toxic extinguishers are?
BCF
70. The correct type of extinguisher to be used in a fltdeck is?
Water glycol
71. The correct type to be used on an aircraft electrical fire is?
BCF
72. The head of and a/c extinguisher is tested for continuity with?
Safety Ohmmeter
73. A fire bottle insulation check is carried out between?
All three pins and earth.
74. An engine fire extinguisher over pressure is indicated by?
Bright red bowl.
75. Before electrically connecting an engine fire extinguisher, you must?
Carry out a no volts test on the connections.
76. When testing a fire detector you would use?
A shroud or long type heater.
77. The balancing cell in a smoke detector unit?
Counteracts differences in supply voltage.
78. When the detector test switch is operated it?
Activates the detecting cell
79. Zero adjustment of the detector is done by physically varying the light?
Received by the balancing cell.
80. In a photo electric type detector, the test function is effected by?
A lamp.
81. Serviceability of the visual indicator filament during test is indicated by?
The illumination of the green pilot light window
82. Airconditioning systems must supply a minimum of?
1.lb air per person per minute
83. The torque of an aircraft starter motor is?
High
84. To limit the stating current of an engine starter motor, resistance is placed?
Series with the armature.
85.The voltage of an ignitor plug on a gas turbine engine is dependant on?
Discharge gap.
86. The conductor in a tersil cable is?
Nickel plated copper
87.A cable marked tersil 22, the number represents?
Cross sectional area.
88. If the cross sectional area of a conductor is increased, resistance wil?
Decrease proportionally.
89. Copper is inferior to aluminium when conducting in comparason to?
Weight.
90. The maximum bonding on an aircraft should be?
0.05 ohms
91. If all three prongs of a bonding tester are shorted together the reading would be?
0.
92. The leads of a bonding tester are?
Critical in length, and resistance is catered for.
93. Before effecting a crimp the ends of the cables should be?
Lightly twisted in the direction of the lay.
94. The number of dots impressed on the insulation of a crimp indicate?
Correct tool was used for effecting the crimp.
95. Can the pressure of the insulation crimp jaws on a red/blue pidg crimping tool be changed?
Yes
96. AC feeder cables are twisted together to ?
Reduce radio interference.
97. The recommended distance between in line crimps is?
10 inches
98. The insulation resistance in undercaridge bays should not normally be less than?
2 megohms.
99. Capacitive circuits should be disconnected when carrying out an insulation check because the tester will?
Give a falsely low reading as the capacitor charges.
100. Circuit testing should be carried out in the following order.
Bonding,continuity,insulation,function.
101. To check the fwd resistance of a diode with an avo, the positive lead should be put to the?
Cathode.
102. After carrying a function test of a circuit, and the circuit turned off?
The fuse/cb should be tripped to check isolation.
103. A 250 volt megger should not be used on?
Electronic equipment.
104. When conducting an insulation check?
The conductors are tested collectively and any suspect tested individually.
105. A heavy duty connection is tested by?
Milli volt at rated current.
106. To find a high resistance or open circuit, carry out?
Continuity test.
107. The primary of the voltage stabilising transformer senses the out put of?
Main TRU
108. A current transformer should always have its secondary either connected or short circuited due to?
A rise in higher secondary voltage.
109. An inverter is used to convert?
DC to AC
110. Anti icing mats are rated in?
Watts/square foot.
111. A filament has the letters MES on its shaft, this means?
Minature Edison Screw
112. The life of a dc fluorescent light can be increased by?
Periodically reversing the supply.
113. The SI unit of luminous intensity is the?
Candella.
114. Increase in temperature causes the fire wire capacitance to?
Increase.
115. The fire warning is cancelled by?
Reducing the fire wire temperature.
116. The outer casing of a fire wire is connected to?
Earth.
117. If the fire warning light remains illuminated after release of the test switch, this indicates?
Low insulation of the fire wire.
118. The test switch of a continuous loop fire detector gives a?
Continuity test.
119. In a paralleled ac generation system, load sharing is for?
Real and reactive load.
120. In a constant frequency ac system, real load sharing is achieved by?
Regulating the generator drive torque.
121. In a constant frequency ac system, reactive load sharing is achieved by regulating?
Voltage regulator.
122. Paralleling in ac constant frequency system is effected by?
Bus Tie Breakers.
In an ac parallel system the normal flt state of the Bus tie Breaker is?
Closed
In a non parallel system, the position is?
Open
An advantage of a star connected genaration system over delta wound is?
2 potentials can be used.
Current in an inductive circuit will?
Increase with a decrease in frequency.
The GCR directly controls?
Excitor field.
Tripping the GCR will?
Trip the GCB and de-excite the generator.
In a voltage regulation system, the current compounding principal is?
To increase total excitor field proportionally to load current.
Using a pulsed width voltage regulation system, with an increase in gen voltage?
Pulse width decreases.
In a constant frequency ac system, the reactive load sharing is achieved by?
Generator excitation.
The magnetic trim coil of a CSD can modify the gen output drive torque?
When gen is operating in parallel on bus bar.
In a parallel ac generator system, load sharing is for?
Real and reactive loads.
The current in the active and reactive load sharing loop is?
Ac
In parallel ac system, real load sharing is achieved by controlling?
Generator drive torque.
Generator auto paralleling circuit controls the?
GCB
The CSD speed trim solenoid is used to trim its speed?
When the geny is in parallel operation.
The load controller is used in?
The real load sharing loop
.
A mutual reactor is used in the?
Reactive load sharing loop.
A mutual reactors output mainly depends on the generator?
Reactive load current.
Over excitation protection applies to?
Parallel ac generation systems.
Differential protection monitors for?
Feeder cable faults.
The reactive load KVA is measured by the product of?
B line current and A-C line voltage.
Over voltage is a passive fault.
A rotary inverter uses?
A dc compound motor.
The diodes in a TRU are connected in parallel?
To reduce the heating effect.
A rotating type field alternator is usually used on aircraft systems.
A rotating field type alternator slip rings carry the?
Field current.
Decreasing the field current in an alternator will?
Decrease the out put voltage
A reistive load on an alternator, will?
Reduce output frequency
An inductive load on an alternator will?
Reduce the terminal voltage.
A stator rotating field applies to?
Synchronous and induction motors
Slip only applies to induction motors.
Which type of motor does not employ a squirrel cage?
Synchronous.
To improve the starting torque of an AC inductive motor the?
Rotor power factor is increased (resistance is increased)
A three phase ac motor has one phase disconnected while running, this will?
Have no effect on the running but it will not start form stationary
In a synchronous motor the rotor is excited by
D.C.
A 3 phase motor with star point earthed can have its direction of rotation reversed by?
Reversing any two phase connections.
An induction motor does not have its rotor connected to any external source of power.
The terminal voltage decrease in an ac generator with increasing resistive load is due to?
Reactance and resistance.
The normal method of controlling an ac generators voltage is to?
Control the generators exciter current.
A basic ac synchronous motor cannot be self starting.
Increasing rotor resistance of an ac induction motor will?
Decrease normal running speed.
Brushless ac generator diodes are mounted in its rotor.
The salient pole rotor is used in?
Synchronous ac generator.
A squirrel cage rotor will be found in?
An induction motor
If a three phase induction motor will not star, it only growls when on?
It is probably a stator phase is open circuit.
During an insulation test on a 200 volt ac generator, the minimum resistance expected ?
1.3 megohms.
An ac generators power is rated as a ?
Product of voltage and current with a power factor.
The CSD/IDG governor speed control screw adjusts?
Frequency.
The electrical trim control fitted to a CSD speed governor is used to adjust?
The output torque.
In a dc motor the armature current flow is?
AC
In a dc motor, reversing field and armature connections will?
Still rotate in the original direction.
The purpose of a commutator in a dc motor is to?
Reverse the armature current.
Effective voltage = applied voltage - back EMF.
In a dc motor the MNA position is normally?
Against the direction of rotation.
Reactive sparking in a dc motor will occur if the brushes are positioned on?
The GNA
Decreasing armature current in a dc motor will?
Decrease the speed.
Copper losses in a dc motor are caused by?
High resistance field windings.
In a dc machine eddy currents occur in the ?
Armature and field pieces.
Laminated construction reduces eddy currents.
Each commutator segment in a dc machine has 2 coil connections
Armature windings remain in place due to a wedge and strapping around the armature
A lap wound armature is used for high current circuits.
A lap wound 8 pole dc machine has 8 brushes.
A wave wound armature dc machine has 2 brushes.
A wave wound machine is used for high voltage circuits.
A 4 pole dc machine, 1 rev is 4 pole pitches.
In a dc machine the polarity of an interpole is the same polarity as?
The last main pole in a dc motor.
Compensating windings ain a dc machine are located at?
The main pole pieces.
Armature torque is proportional to?
Armature and field strength.
Rotational speed of a dc motor is proportional to ?
Armature and field currents.
Increasing the voltage applied to th e armature causes?
Rotational speed to increase.
Reversing the supply to a permanent magnetic field motor will cause?
Direction reversal.
Rotational speed of a dc motor may be controlled by?
Either field or armature resistance.
The dc shunt motor has?
Low starting torque.
To decrease the rpm of a dc shunt motor, the?
Field resistance is decreased.
Decreasing the field current of a dc generator will?
Decrease output voltage.
The purpose of the commutator in a dc generator is to?
Convert the generated ac to a rectified dc.
In a dc generator with armature reaction, the MNA moves?
With the direction of rotation.
In a dc motor, the MNA moves?
With the GNA
Increasing the number of armature conductors in a dc generator will?
Increase induced EMF.
Compensator windings carry armature current.
Increasing the load on a PMG will?
Reduce terminal voltage by a small amount.
The series wound generators terminal voltage will?
Increase with an increase in load.
The shunt wound generator is normally started off load.
The shunt wound generator is controlled by variable resistance in?
Series with the field.
In a cumulative compound wound generator, the?
Series and shunt fields assist each other.
Shunt generators are mainly used on aircraft.
Minimum brush length is measured on the longest side.
A dc machine commutator is cleaned using lead free petrol.
The expected brush spring tension on a 6kw dc generator is?
28 oz to 36 oz.
Running a dc generator on no load for long periods will cause?
The commutator to glaze over.
The minimum insulation value on a 28V dc machine is?
0.5megohms
dc generator voltage is controlled using the ?
Field strength.
Before engine start the carbon pile is fully compressed.
The carbon pile in a voltage regulator is?
Connected in series with the generator field.
Transistor voltage regulators operate with pulse control.
The ballast resistor in a carbon pile regulator is selected to?
Set the correct ampere turns in the voltage coil.
The dc generator switch directly controls?
The generator contactor.
The differential cutout contacts are closed using the?
Voltage coil only.
Indication of a short circuit in the remote ammeter shunt is that the?
Generator operates normally but the ammeter reads zero.
If a dc generator main contactor is welded closed, it becomes a motor on shut down.
The engine keeps turning while electricity is supplied.
With rising generator voltage in a dc system the?
Undervolt relay closes before the differential relay.
In a dc system, the differential cut out contacts are closed using?
The differential coil only
The differential cut out opens using the?
Series coil only
In a dc system, when reverse current flow is first detected, initial action is?
Differential contacts to open.
In this system, over volts condition is sensed by monitoring the?
The voltage of the field.
An over voltage condition will?
De-excite the generator (trip).
The differential cut out coil senses the difference in generator out put and bus bar?
When the undervolt relay is closed.
If the dc generator fault warning remains illuminated, while indicating 28V it could be?
The under volt relay has failed to close.
The equalising coil in a carbon pile regulator?
Modifies the effect of the voltage sensing coil.
Load sharing in a dc system is achieved by?
Changing the generator field resistance.
Equalisation in a dc system, equalises the generators out put in terms of?
Power.
The voltage used to circulate the equalising current is approximately?
0.05 Volts.
With a vibrating contact type voltage regulator, overload protection is achieved by?
Limiting field current.
Engine starting system does not have to be protected against reversed polarity.
The expected range of a dc generator speed is?
5000 to 8000 rpm.
During load sharing adjustment on a dc system?
A first grade voltmeter is used.
Load sharing adjustments are carried out with?
One generator at a time on load.
The minimum insulation resistance you would accept on a 28V dc generator is?
0.2 megohm.
In a dc system, the normal range of a voltage trimmer is?
3 volts
voltage adjustment on a dc system is carried out?
With one generator at a time off load.
On a dc system, load sharing is checked with?
All generators on load.
An open circuit voltage coil in a carbon pile regulator, wil cause?
Voltage increase to over volt condition.
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Monday, September 28, 2009
EASA Module 4 Questions
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