Module 4 v

1. A junction diodea) has one p-n junctionb)is similar to a vacuum diode but cannot rectifyc) can handle only small currents

2. A germanium diode is used fora) voltage stabilisationb)rectificationc) signal detection

3. A germanium diodea) has a lower forward bias voltage than a silicon diodeb)has a higher forward bias voltage than a silicon diodec) has the same forward bias voltage as a silicon diode

4. a VLSIC hasa) less than 1000 gatesb)more than 1000 gatesc) more than 10,000 gates

5. A momentary input at the reset input of a flip flop willa) reset the true output to 0b)reset the true output to 1c) clock in new data from the data inputs

6. Which type of flip flop has only 1 data inputa) RSb)JKc) D

7. A low pass filter hasa) a capacitor in series and an inductor in parallelb)a capacitor in parallel and an inductor in seriesc) both capacitor and inductor in parallel

8. When you use an op amp as a buffer it hasa) high input impedance and low output impedanceb)low input impedance and high output impedancec) the same input an output impedance

9. What switches off a thyristor?a) Remove the gate voltageb)Remove supply voltagec) Reverse bias gate

10. When an SCR is switched on it hasa) high resistanceb)low resistancec) no change in resistance

1. What is required for the switching of a monostable multivibratora) one trigger pulse to switch on and another to switch offb)one trigger pulse to both switch on and offc) one trigger pulse to switch on and two trigger pulses to switchoff

2. A transistor at saturation hasa) high resistanceb)low resistancec) zero resistance

3. A capacitor resistor coupled multistage amp letsa) AC and DC pass to the next stageb)AC pass onlyc) DC pass only

4. An oscillator operating at its natural frequency has feedback whichisa) inphaseb)90 degrees out of phasec) 180 degrees out of phase

5. What type of diode when forward biased holes and electrons recombineproducing photons?a) gunnb)LEDc) photodiode

6. What type of pulse is required to switch on a SCRa) positiveb)negativec) positive and negative

7. Which mathematical operation is performed by a modulator amplifier?a) Additionb)Subtractionc) Multiplication

8. What is meant by a bistable circuit?a) The circuit has 2 stable states and will stay in which one it is putb)The circuit has 2 stable states and will stay in both at the sametimec) The circuit has 1 stable state and it can be negative or positive

9. A zener diode is designed to operatea) above its breakdown voltageb)below its breakdown voltagec) either above or below its breakdown voltage

10. A JFET isa) voltage sensitiveb)current sensitivec) either of the above depending on resistance in the circuit

1. A triac is a type ofa) thyristorb)thermistorc) transistor

2. A piece of pure Germaniuma) has a deficit of electronsb)is electrically stablec) has an excess of electrons

3. If a junction diode is reverse biased too far, the output currentwoulda) cease to flowb)increasec) reverse direction

4. An RC connected amp hasa) no AC acrossb)no DC acrossc) even amounts of d.c and a.c across

5. When a PN junction is forward biased, it conducts viaa) majority carrierb)minority carrierc) intrinsic carrier

6. Thermal runaway in a transistor refers toa) high current flow when temperature increasesb)low current flow when temperature increasesc) high current flow when temperature decreases

7. When is maximum voltage induced into the rotor of a control synchrotransformer?a) 90 degrees (null position)b)0 degreesc) When spinning fast

8. Resistors and capacitors are used to couple stages of amplifiers sothata) only d.c can be appliedb)equal amounts of a.c and d.c can be appliedc) only a.c can be applied

9. An astable multivibrator is aa) free running vibratorb)one which requires an input to switch on and offc) one which requires no input whatsoever

10. Op amps use what power supply?a) 26v a.cb)5v - 15v d.cc) 26v d.c

1. To check the output of a synchro stator it would be preferable to usea) an Avometerb)a Valve Voltmeterc) a Cambridge Bridge

2. Synchro capacitors are connected into synchro systems toa) minimize the torque synchro stator current at nullb)increase the accuracy of the control synchroc) act as spark suppression due to wear of the slip rings

3. The purpose of the fly wheel incorporated in a synchroa) is to increase the driving forceb)to prevent oscillationsc) to prevent insect ingress

4. In a slab desynn transmitter thea) pick-offs form part of the circuit resistanceb)pick-offs rotate on the slab resisterc) pick-offs are connected to a spark suppressor

5. If, in a servo system, the amplitude from the feedback system isbelow normal, the servo willa) oscillateb)be sluggish in operationc) be overdamped

6. A desynn instrument has a positive irregular increasing error, youwould adjusta) lever lengthb)lever anglec) lever angle and lever length

7. Torque synchro receiver bearing friction will causea) huntingb)misalignmentc) improved accuracy

8. A control synchro system pointer isa) actuated by a permanent magnetb)displaced by the torque of the statorc) motor driven

9. A D.C. signal converted to a phase sensitive A.C. isa) demodulationb)phase conversionc) modulation

10. If velocity feedback in a servo system is above optimum, this willcausea) sluggish operationb)huntingc) has no effect

1. A device which has a high input impedance, low output impedance andhigh voltage gain is aa) Class A ampb)Class B ampc) Op-Amp

2. In an integrated circuit, the components are mounted bya) wires connecting them using conformal coatingb)a three dimensional process with no connections between them requiredc) metal oxide film etched onto surface

3. For a NPN transistor to conduct the collector circuit has to bea) more positive than the emitterb)more positive than the basec) less positive than the emitter

4. The amount of rate feedback from a tachogenerator isa) proportional to speedb)inversely proportional to speedc) constant for all servo speeds

5. When forward biased, current flow is mainly due to thea) majority carriersb)minority carriersc) germanium bias junction

6. When forward biased thea) positive lead is connected to the N type and negative to the P typeb)positive lead is connected to the P type and negative to the N typec) positive lead is connected to both N and P type

7. In a PNP transistor, which way does conventional current flow?a) Base to emitterb)Collector to emitterc) Emitter to Collector

8.In the Zener Diode suppressor shown, point X in respect to point Y shouldbe a) more negativeb)more Positivec) either positive or negative

9. In an integrated circuit, the components are inserteda) manuallyb)automaticallyc) by doping in successive layers

10. The typical voltage drop across an L.E.D isa) 2Vb)4Vc) 6V

1. In an electronic circuit with an operational amplifier connected inthe push-pull configuration, the circuita) decreases impedanceb)utilizes both sides of the input signalc) blocks half of the input signal

2. Pin 3 on an op-amp has a + symbol. This designatesa) positive offset nullb)positive input DC pinc) non-inverting input

3. An advantage of a FET when compared to a bi-polar transistor isa) the input resistance is lowerb)the switching time is quickerc) the input resistance is higher

4. The semiconductor substrate used in 'chips' is most commonlya) germaniumb)siliconc) phiidide

7. What control system is used on an input that gives a controlledpredetermined output?a) Open Loopb)Closed Loopc) Control Servo

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Module 4 vi

8. Increasing velocity feedback from optimum will givea) sluggish performanceb)faster performancec) no change on the output

9. A rate control servo system with a steady input voltage will givea) constant speedb)increasing speedc) decreasing speed

10. Where are decoupling capacitors used in digital circuits?a) Between pins 1 & 8b)Close to the +ve pinc) Close to the ve pin

1. What are the majority carriers for a forward biased PN junctiondevice?a) Electronsb)Holesc) Electrons and holes

2. The resistance measured using an AVO between the Collector andEmitter of a transistor isa) same both waysb)smaller Collector to Emitterc) higher Collector to Emitter

3. Germanium in its pure state isa) neutralb)positively chargedc) negatively charged

4. Common Collector has the following characteristicsa) Medium Voltage Gain, High Current Gain, Non-Inverted Outputb)Low Voltage Gain, High Current Gain, Inverted Outputc) Medium Voltage Gain, Low Current Gain, Inverted Output

5. Two push-pull transistors have what commoned?a) Basesb)Collectorsc) Emitters

6. In a Common Emitter Amplifier RE is used fora) biasingb)stabilisationc) load control

7. If the reverse bias voltage across a diode is too higha) load current increases rapidlyb)load current reversesc) load current reduces to zero

8. The rotor coil of a synchrotela) is stationaryb)rotatesc) rotates only when a current flows in it

9. An increase in amplitude of a rate feedback signal will causea) sluggish servo operationb)reduced huntingc) instable operation

10. An increase in negative feedbacka) increases system sensitivityb)decreases system sensitivityc) will make the driven device continuously rotate

1. An integrated circuit is manufactured bya) computer hardware, which use individual circuits on ribbonb)doping impurities into layers of intrinsic materialc) etching copper tracks onto an insulating board

2. A de-coupling capacitor in a PCB is used toa) minimise transient currentsb)pass a.c onlyc) pass d.c only

3. A monostable vibratora) is switched on by a trigger pulse then within a pre-set time willeventually return to its original stateb)uses a trigger pulse to turn on and the same pulse to turn offc) uses one pulse to turn on and another to turn off

4. Position feedback is used toa) ensure control surface moves to the demanded position by thecontrolsb)to prevent control surface oscillations while the surface is beingmovedc) indicate to the pilot the position of the load

5. The output from a control transformer isa) torqueb)AC voltagec) DC voltage

6. The stator output voltages from a synchro resolver area) DCb)AC single phasec) 3 phase

7. The purpose of synchro capacitors in a differential synchrotransmission systema) to reduce stator currentb)reduce rotor currentc) reduce stator circuit impedance

8. A typical use for resolver synchros isa) in compass comparitor unitsb)engine power instrumentationc) fly by wire system

9. The purpose of a flywheel in a synchro receiver indicator is toa) prevent spinning or oscillationb)encourage spinningc) increase driving torque

10. A linear variometer isa) a special synchro giving ac output proportional to shaft angleb)a special auto transformer for synchro system power suppliesc) an alternative term for a desynn system

1. In a synchrotel the rotating winding isa) the statorb)rotorc) neither

2. The receiver rotor in a torque synchro system oscillates over an arcof approx 75 degrees. The probable cause isa) short circuit between two stator linesb)two stator lines reversedc) one stator line open circuit

3. Synchro capacitors are fitteda) to provide critical dampingb)to make additional damping features unnecessaryc) to improve sensitivity and accuracy

4. The output of a control transformer is madea) phase and amplitude sensitive by direction and magnitude of thetransmitter rotor movement respectivelyb)phase and amplitude sensitive by magnitude and direction of thetransmitter rotor movement respectivelyc) phase sensitive by transmitter rotor excitation and amplitudesensitive by direction of transmitter rotor movement

5. A transistor is used ina) current amplifierb)voltage amplifierc) both

6. An LED which emits green light usesa) gallium ****nide phosphideb)gallium phosphidec) gallium ****nide

7. An LED which emits red light usesa) gallium ****nide phosphideb)gallium phosphidec) gallium ****nide

8. A photodiode is operated undera) reverse bias conditionsb)forward bias conditionsc) reverse or forward bias conditions

9. To increase capacitance of a varactor diodea) reverse bias voltage is increasedb)forward bias voltage is decreasedc) reverse bias voltage is decreased

10. Which diode has a lower forward bias voltage?a) siliconb)germaniumc) both the same

1. A Zener diode is used fora) rectificationb)voltage stabilisationc) voltage regulation

4. A thyristor SCR is aa) unidirectional deviceb)bi-directional devicec) multidirectional device

5. A bi-directional TRIAC has two SCRs connected ina) series parallelb)parallel seriesc) inverse parallel

6. A thyristor can be forward biased bya) positive pulseb)negative pulsec) positive or negative pulse

7. 'N' type materials are doped witha) acceptorsb)donorsc) acceptors and donors

8. A junction diode if reverse biased too far, the output willa) increaseb)stopc) reverse

9.The input of this circuit will bea) integratedb)differentiatedc) logarithmic

10. The most suitable class of amplifier for a radio transmitter isa) Ab)Bc) C

2. What is the base material of a PCB?a) Insulatorb)Conductorc) Semiconductor

3. What does the output voltage of an op-amp depend upon?a) The resistors in the circuitb)The op amp bandwidthc) The gain of the op-amp

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Module 4 iv

1. The cogging effect in synchros is rectified bya) using carbon brushesb)using an elliptical cogc) skewing the rotor

2. A transistor is said to be in the quiescent state whena) no signal is applied to the inputb)it is unbiasedc) no currents are flowing

3. In an unbiased p-n junction, current flow isa) due to the diffusion of minority carriers onlyb)zero, because no charges are crossing the junctionc) zero, because equal but opposite currents are crossing thejunction

4. Reversal of the power supply to either the transmitter or thereceiver of a torque synchro system woulda) cause a 180o displacement between the transmitter and the receiverb)have no effect on the indication, but would cause a heavy current toflowc) make the receiver rotor rotate in the opposite direction

5. Torque synchro systems are normally used when thea) mechanical load is lowb)mechanical load is highc) system accuracy is of extreme importance

6. A common base transistor circuit is so called becausea) the base region is located between the emitter and collector regionb)the base is n-type materialc) the base is common to the emitter and collector circuits

7. What device transfers one energy type to another?a) Transmitterb)Transducerc) Transponder

8. Which way does conventional current flow in a PNP junction?a) Collector to emitterb)Emitter to basec) Collector to base

9. Electrical power is supplied to a synchro rotora) directlyb)through slip ringsc) through a commutator

10. The purpose of a flywheel incorporated in a synchro is toa) increase the driving forceb)prevent oscillationsc) prevent insect ingress

1. In an operational amplifier, the two input waves are the sameamplitude, same frequency, but exactly anti-phase. What would the outputbe?a) Doubleb)Zeroc) Half

2. A thyristor has which of the following?a) High resistance when switched onb)High resistance when switched offc) A positive temperature coefficient

3. On an integrated circuit the hole in the top left corner is pin 1.The pins are counteda) clockwiseb)anticlockwisec) from left to right

4. With reference to the circuit shown below, how is the transistorconfigured?a) Common emitterb)Common collectorc) Common base

5. In the circuit diagram above, R1 and R2 are used toa) set the transistor gainb)set the DC bias levelc) increase the base voltage

6. In a synchro system, if two stator lines are crossed the receiverwilla) not be affectedb)be 180o outc) reverse direction

7. In the following Boolean algebra statement, which gate is described?F = A + B + Ca) Orb)Notc) And

8. In an E and I signal generator at datum, the voltage on the secondarywindingsa) are equal and oppositeb)is maximumc) is zero

9. In a synchro resolver, the stator coils are at what angle in relationto one another?a) 45 degreesb)80 degrees c) 90 degrees

10. In a synchrotel, thea) rotor coil is fixed and the stator coil movesb)rotor coil and stator coil is fixedc) stator coil is fixed and the rotor coil moves

1. On a PCB, a decoupling capacitor is used to get rid of transientcurrents between which points?a) The electronic circuit and the aircraft groundb)Interspaced along the circuitc) The negative rail and the rest of the circuit

3. In an LED, what is used to make the colour?a) The doping materialb)The electronsc) The plastic lens cover

4. An atom with 5 electrons in its outer shell is part ofa) an N type materialb)a P type materialc) a C type material

5. In a FET, the junction connections are calleda) drain, source and gateb)base, collector and emitterc) drain, collector and junctions

6. In the Boolean algebra statement below, the gate described isF = A.B.Ca) Nandb)Norc) And

7. With a small amplitude voltage, what type of diode would you use toproduce the output waveform?a) Shottkyb)Gunnc) Zener

8. An increase in negative feedback to the servo amplifiera) increases amplifier stabilityb)decreases amplifier stabilityc) has no effect

9. How is a push-pull transistor arrangement connected?a) emitter to emitterb)collector to collectorc) base to base

10. Thermal runaway in a transistor is caused bya) excessive heat causing maximum current flowb)excessive heat causing minimum current flowc) low heat causing minimum current flow

1. A single integrated circuit Op Amp has how many pins?a) 4b)7c) 8

2. What is the output of the amplifier shown below?a) 0Vb)3Vc) 5V

3. A thyristor is commonly used fora) voltage regulationb)overvolts regulationc) rectification

4. A diode which emits photons when conducting is aa) zenerb)varactorc) light emitting

5. Avalanche breakdown occurs whena) forward bias becomes excessiveb)forward bias exceeds a certain valuec) reverse bias exceeds a certain value

6. The electrodes of an SCR area) anode, cathode, sourceb)source, drain, gatec) gate, cathode, anode

7. What gives an LED its colour?a) A gasb)The coverc) Composition and impurity of the compound

8. For conduction of a transistor the emitter junction isa) fwd biasedb)reverse biasedc) fwd or reverse as appropriate to the input signal

9. In a PNP transistor which way does conventional current flowa) base to emitterb)collector to emitterc) emitter to collector

10. Infinite gain, infinite input impedance & zero output impedance ischaracteristic of aa) Class A ampb)Class B ampc) Op amp

1. Forward voltage of a silicon diode isa) 0.6Vb)0.2Vc) 1.6V

2. An advantage of a common emitter isa) it is a voltage followerb)it has high power gainc) it has high voltage gain

3. What amplifier is biased at cut offa) Ab)Bc) C

4. When testing a transistor with an ohmmeter, what is the resistance ofthe emitter/collector?a) High resistance one wayb)High resistance both waysc) Low resistance both ways

5. What is the typical volts drop across an LEDa) 1.6Vb)0.2Vc) 0.4V

6. What diode gives off light photons when forward biaseda) LEDb)Shottky diodec) Gunn diode

7. A logic circuit with more than one gate will havea) one of 2 states of logic outputb)2 or more outputsc) an analogue output

9. In a synchro, what is used to convert signals from one form toanother?a) Transmitterb)Transducerc) Transformer

10. Components on an integrated circuit area) in the solidb)don't need themc) on the surface

1. What diode is used to stop power spikes in a coil?a) Two directional zener diodeb)Shottky diodec) Gunn diode

2. The anode of a diode is connected to a +4v DC supply and the cathodeis connected to a +2v DC supply. The diode isa) forward biased not conductingb)reverse biased not conductingc) forward biased conducting

3. Using electron flow in a diode the current flows froma) Anode to Cathodeb)Cathode to Anodec) Cathode to Base

4. A control surface position feedback signal isa) proportional to surface positionb)inversely proportional to surface positionc) non-linear

5. In a PNP transistor, conventional current will flow whena) the emitter is more positive than the baseb)the base is more positive than the emitterc) the collector is more positive than the emitter

6. An E&I transformer out of datum hasa) equal and opposite voltages in each windingsb)unequal and opposite voltages in both windingsc) no voltage in either winding

7. A gyro will providea) rate feedbackb)velocity feedbackc) positional feedback

8. In a common collector circuit the output and input area) out of phase by 90ob)in phasec) out of phase by 60o

9. In velocity feedback the signal isa) in phaseb)out of phasec) equal to the error signal

10. When a hole diffuses from the p region to the n regiona) it becomes a minority carrier in the n regionb)lowers the potential barrierc) raises the potential barrier

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Module 4 iii

1. The junction barrier offers opposition to onlya) holes in the p-regionb)free electrons in the n-regionc) majority carriers in both regions

2. An increase in velocity feedback willa) decrease the speed the load movesb)increase the speed the load movesc) have no effect on speed

3. A two phase motor will stop whena) the reference phase is reversedb)the control phase is reversedc) the control phase is zero

4. A tachogenerator output isa) variable frequency, constant voltageb)variable voltage, constant frequencyc) variable frequency, variable voltage

5. Rate feedback can be obtained from aa) synchrob)tachogeneratorc) potentiometer

6. Positional feedback can be obtained from aa) synchrob)tachogeneratorc) potentiometer

7. The frictional force in a servomechanism that is proportional tospeed is calleda) stictionb)coulomb frictionc) viscous friction

8. The 'null' point in a control synchro is when the two rotors area) at 90o to each otherb)parallel to each otherc) wired in series

9. If two of the stator leads are cross connected in a control synchrosystem, a 25o clockwise rotation of the input rotor would result in theoutput rotora) moving 25o clockwiseb)moving 25o anticlockwisec) moving 180o to rectify the defect

10. Damping in a servomechanism is easier to apply ifa) the mechanism is light and has low inertiab)the mechanism is heavy and has high inertiac) the mechanism is light and has high inertia

1. Reverse biasa) lowers the potential barrierb)raises the potential barrierc) greatly increases the majority carrier current

2. If the electrical connections to the feedback generator in a controlsynchro system were disconnected, thea) motor would run in the wrong directionb)input signal to the amplifier would reducec) system would tend to oscillate

3. An increase in servo amplifier gaina) reduces the speed of the systemb)increases system responsec) reduces tendency to hunt

4. In a control synchro the stator current ceases to flow when thea) CT rotor is at nullb)two rotors are alignedc) power is removed

5. The term 'velocity lag' refers to aa) speed errorb)position errorc) acceleration error

6. The rotor of an AC tachogeneratora) has skewed slotsb)has a copper, brass or aluminium cylinderc) rotates at constant speed

7. A servo system with transient negative velocity feedbacka) is damped with little velocity lagb)is damped with high velocity lagc) is underdamped with high velocity lag

8. To reverse the direction of rotation of a two phase induction motora) reverse the polarity of the control phaseb)reverse the polarity of both the control phase and reference phasec) shift the reference by 90o

9. In a rate servo (speed control) the signal into the servo amplifierisa) input voltage plus tachogenerator outputb)input voltage minus tachogenerator outputc) input voltage plus position feedback voltage

10. Loss of DC to a servo amplifier causes the motor toa) run continuouslyb)stopc) reverse

1. Avalanche breakdown occurs whena) forward current becomes excessiveb)forward bias exceeds a certain valuec) reverse bias exceeds a certain value

2. An AC servo demand can be converted to drive a DC motor by theintroduction of aa) rectifierb)modulatorc) demodulator

3. Synchro indicator systems are used when the indication is required tomovea) a fraction of the input distanceb)slower than the input ratec) at the same rate as the input

4. A linear variable differential transformer is used to measureposition feedback wherea) 360o of rotation and high angular accuracy is requiredb)accuracy is of limited importance but robust construction andreliability is importantc) an output whose phase is related to direction of movement andamplitude linear over a wide range

5. A low frequency sinusoidal input will cause a closed loopservomechanism load toa) move to a demand position with no overshootb)move backwards and forwards at the input frequencyc) move to the demand position and then return to the datum positionwithout any overshoot

6. To reduce oscillations about a demand positiona) the amount of velocity feedback would be decreasedb)the amount of velocity feedback would be increasedc) the amount of position feedback would be increased

7. If a servo amplifier is suffering from drifta) the load would move to a new position, proportional to the drift andstay thereb)the load would move to a new position, proportional to the drift andthen return back to the datum positionc) the load would oscillate about the datum position

8. In a transient velocity feedback circuit, the tachogenerator outputis summated with the demand voltagea) only when the load is slowing downb)at all times when the load is movingc) only when the load is speeding up or slowing down

9. Positive feedback applied to a servomechanisma) decreases the response of the systemb)opposes the demand signalc) increases the response of the system

10. A differential synchro rotor consists ofa) one winding parallel to the transmitter rotorb)two windings at 90o apartc) three windings at 120o apart

1. A differential synchro transmitter used for addition hasa) the TDX S1 and S3 connections cross connected to the TXb)the TDX S1 and S3 connections cross connected to the TRc) 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 rapidincrease in current flow for a relatively small increase in voltage occursa) only after the forward bias exceeds the potential barrierb)when the flow of minority carriers is sufficient to cause an avalanchebreakdownc) when the depletion layer becomes larger than the space charge area

3. An LVDT hasa) an output winding which is wound in series oppositionb)an input winding whose voltage will change with load movementc) an output winding whose voltage and frequency is linear to loadangular movement

4. A diode connected across a relay coil is used toa) allow the coil to energize with only one polarityb)cause a delay in switching onc) dissipate coil spikes on switch off

5. Differential transmitters are used toa) add or subtract two electrical signalsb)add or subtract a mechanical signal to an electrical synchro signalc) increase the operating speed of the synchro receiver

6. To convert a differential synchro from subtraction to addition youwoulda) reverse the reference phase supplyb)change over two rotor and stator connectionsc) change over all three stator windings

8. When resolving a Cartesian input to a Polar outputa) the inputs are a shaft angle and a voltageb)the outputs are two voltagesc) the inputs are two voltages

9. To check the forward resistance of a diode with a multimeter, thelead connected to the positive terminal is put to thea) anodeb)cathodec) either anode or cathode

10. A resolver synchro output is obtained from a rotor witha) one single coilb)two coils at 90o to each otherc) three coils at 120o to each other

1. The input and output signals of a common emitter amplifier area) equalb)out of phasec) in phase

2. The output of a resolver synchro isa) dependant upon the position of the rotor onlyb)proportional to the speed of input rotationc) a function of the rotor position and excitation voltage

3. The rotor of an autosyn position indicating system isa) a permanent magnetb)an electromagnetc) spring controlled

4. A band pass filter excludes frequenciesa) above the frequency required onlyb)below the frequency required onlyc) above and below the frequency required

5. The rotor of a magnesyn transmitter isa) a dc electromagnetb)a permanent magnetc) an ac electromagnet

6. In general the accuracy of a synchro system increases if thea) stator current is highb)stator current is lowc) rotor current is high

7. Torque synchro systems are normally used when thea) mechanical load is lowb)mechanical load is highc) system accuracy is of extreme importance

8. In a resolver synchro the stator windings are electrically disposedbya) 90ob)120oc) 180o

9. The induced signal in the output coils of the magnesyn systema) de-saturates the soft iron coreb)damps the pointer oscillationsc) is of a value of 800 Hz

10. The direction of the induced (secondary) magnetic field in a synchrotransmittera) is 90o to the primary magnetic fieldb)in the same direction as the primary fieldc) is in the opposite direction to the primary field

Module 4 ii

8. Mechanical friction in a servo results ina) reduced gainb)increased dampingc) increased inertia

9. The position feedback signal isa) in phase with the input demand signalb)in anti-phase with the demand signalc) phase advanced by 90o with respect to the input signal

10. A servo system that overshoots and oscillates isa) under dampedb)over dampedc) critically damped

1. The power supply to a torque synchro system is connected toa) the transmitter statorb)the transmitter rotor onlyc) the transmitter and receiver rotors

2. If the rotor of the receiver in a torque synchro system was preventedfrom aligning with the transmitter rotor, thena) the transmitter rotor will turn to align with the receiver rotorb)the receiver will overheatc) a high current will flow in the stator windings

4. A zener diodea) stabilizes voltage at a predetermined levelb)allows current to flow in one directionc) acts like a switch

5. The common collector amplifier is sometimes called the emitterfollower circuit becausea) the emitter current follows the collector currentb)the emitter voltage follows the base voltagec) the emitter voltage follows the collector voltage

6. In a toroidal resistance transmitter indicator system, the powersupply is connected toa) the brushesb)the resistor slabc) the rotor

7. When a servo has reached its null and stopped, the velocity feedbackisa) zerob)maximum and anti-phasec) maximum and in phase

8. The primary purpose of rate feedback in a positional servo system istoa) ensure minimum response timeb)prevent excessive overshootc) ensure system linearity

9. In an AC rate servo, a steady input will result in the servomotora) oscillating about a new datumb)rotating at a constant speedc) rotating to a new datum position

10. An E&I bar output at datum hasa) no induced voltage in the secondary windingsb)an imbalance of voltages in the secondary windingsc) equal and opposite voltages induced in the secondary

1. A non-inverting op-ampa) has a non-inverting input and an inverting outputb)has an inverting input and a non-inverting outputc) a non-inverting input connection only

2. Amplifiers may be classified asa) common emitter or common collector amplifiersb)voltage amplifiers or impedance amplifiersc) voltage amplifiers or power amplifiers

3. What is a shottky diode used for?a) Very high frequency applicationsb)Stabilsationc) 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 60oclockwise would bea) the receiver would move 60o clockwiseb)the receiver would move 120o anticlockwisec) the receiver would move 60o anticlockwise

5. The control windings of a two phase servomotor is supplied with ACvoltage ofa) constant amplitudeb)variable phasec) variable amplitude, variable phase

6. In a torque synchro that includes a differential synchro the powersupply is connected toa) the transmitter rotor onlyb)the transmitter and receiver rotors onlyc) all three rotors

7. A differential synchro rotor has a) three windingsb)two windingsc) one winding

8. If the rotor of a control synchro sticksa) the system huntsb)high current will flowc) the position feedback will oscillate

9. With the reversal of the connections to the rotor of the transmitterof a torque synchro, the position of the receiver rotor will bea) unchangedb)changed by 120oc) changed by 180o

10. The application of a 'stick-off' voltage to a control synchro servosystem isa) to overcome the effect of static frictionb)to overcome the effect of viscous frictionc) to prevent alignment to a false null

1. When removing a microprocessora) no damage is done by static dischargeb)considerable damage can be done by static dischargec) ensure the power is OFF to avoid static discharge

2. An amplifier can provide both voltage gain and current gain when itis connected in thea) common base configurationb)common emitter configurationc) common collector configuration

3. How do you increase voltage gain of an amplifier?a) decrease base circuit biasb)decrease input resistancec) increase input resistance

4. In a resolver synchro the stator windings are electrically displacedbya) 90ob)120oc) 180o

5. A servo system may include a brake, an automatic trim system is oneexample where a brake is used. The brake isa) applied during trimming to prevent oscillations about the demandpositionb)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 witha) one single coilb)three coils at 120oc) two coils at 90o

7. In a control synchro the stator current ceases to flow whena) the CT rotor is at nullb)when the two rotors are alignedc) when power is removed

8. In a speed control servo system (rate control), the purpose of thetachogenerator isa) to make the velocity proportional to servo demandb)to make the deflection proportional to servo demandc) to make it run at constant speed

9. The result of reversing the rotor connections to the receiver of atorque synchro system is that the rotor positiona) is unchangedb)is changed by 120oc) is changed by 180o

10. The rotor of a torque synchro indicator isa) supplied with an excitation voltageb)short circuitedc) connected in series with the transmitter stator coil

1. When a hole diffuses from a p-region to the n-region ita) becomes a minority carrier in the n-regionb)lowers the potential barrierc) raises the potential barrier

2. How are the pins numbered on an op-amp IC?a) counter clockwise from the dotb)clockwise from the dotc) from left to right from the dot

3. To increase the output of a servo amplifier, it is necessary toa) reduce the tacho feedbackb)increase the tacho feedbackc) increase the position feedback

4. Angular displacement of the control coils with respect to thereference coils in a two phase induction motor area) 0o, 180ob)90o, 270oc) 90o, 120o

5. a two phase induction motor used in a servomechanisma) will always require a starterb)is self starting under light loadsc) runs with no slip

6. A servomotor having only a tachogenerator as a feedback device willa) vary its speed with input error voltageb)have a constant speed for any given input voltagec) null out at a position dependant upon input error voltage

7. A hysteresis servo motor is used in a servomechanism becausea) it has good starting characteristicsb)good speed/voltage relationshipc) low inertia

8. The null position of a torque synchro system is whena) the TX and TR rotors are parallel to each otherb)the TX and TR rotors are 90o to each otherc) the TX and TR rotors are 120o to each other

9. Reversal of two of the stator connections on a torque synchroreceiver would causea) the transmitter to become the receiverb)the output to move the same direction as the inputc) the output to move the reverse direction to the input

10. An AC tachogenerator stator hasa) two windings 180o apartb)three windings 120o apartc) two windings 90o apart

1. A junction diodea) has one p-n junctionb)is similar to a vacuum diode but cannot rectifyc) can handle only very small currents

2. When the rotor of an AC tachogenerator is stationary, the rotor hasa) no circulating currentsb)low circulating currentsc) no magnetic fields

3. The output of a tachogenerator should bea) sinusoidalb)exponentialc) linear

4. With a constant input to a speed control servo, the servo motora) moves to a certain positionb)moves at a constant speedc) oscillates, but otherwise does not move

5. A closed loop servomechanisma) must only have position feedbackb)must have both position and velocity feedbackc) can have either position or velocity feedback

6. Critical damping in a servomechanism isa) the point which allows just one overshoot before the load comes torestb)the amount of damping that results in the load just not oscillatingc) the critical damping required for the optimum damping of theservomechanism

7. In a control synchro system the power supply is connected to thea) transmitter rotor and amplifierb)receiver rotor and amplifierc) transmitter and receiver rotors

8. Reverse rotation of a control transformer rotor can be caused bya) connections between the transformer rotor and the amplifier reversedb)connections to the transmitter rotor reversedc) short circuit between two transmission lines

9. Velocity feedbacka) opposes the demand inputb)assists the demand inputc) prevents dead space errors

10. Velocity lag can be decreased bya) introduction of an integratorb)keeping the error detector (summing point) output as low as possiblec) decreasing the coulomb friction in the system

Module 4 i

1. What gives the colour of an LED?a) The plastic it is encased inb)The active elementc) The type of gas used inside it

2. A germanium diode is used fora) rectificationb)voltage stabilizationc) modulation

3. Why is a diode put in parallel with an LED?a) To protect it from ACb)So it will work only above a certain voltagec) So it will work only below a certain voltage

4. When testing the forward bias of a diode with a multimetera) the positive lead of the ohmeter is placed on the cathodeb)the positive lead of the ohmeter is placed on the anodec) it does not matter which terminal the positive lead of the ohmeteris placed

5. In an NPN transistor the P is thea) collectorb)basec) emitter

6. The output of a tachogenerator isa) proportional to speed of rotationb)proportional to positionc) proportional to acceleration

7. AC power is supplied toa) torque receiver onlyb)torque transmitter onlyc) both the torque receiver and torque transmitter

9. How is a PCB protected after manufacture?a) With non-conductive varnishb)With waxc) By conformal coating

10. A differential synchroa) can only be used as a transmitterb)can only be used as a receiverc) can be used as either a transmitter or a receiver

1. Which of the following describes the characteristics of a Thyristor?a) High voltage handlingb)High current handlingc) High power handling

2. A semiconductor doped with an element having a valency of 5 willproducea) an N type materialb)a P type materialc) either an N type or a P type depending on what type ofsemiconductor material is used

3. What are the ideal characteristics of an Op Amp?a) Infinite gain, infinite input Impedance and infinite outputimpedanceb)Low gain, infinite input Impedance and zero output impedancec) Infinite gain, infinite input Impedance and zero output impedance

5. What gate does the following Boolean expression representF = A.B.Ca) ANDb)ORc) NOT

6. What gate does the following Boolean expression representF = A+B+Ca) NOTb)NORc) OR

7. To decrease the voltage gain of a common emitter amplifier youwould increase the resistance in thea) base circuitb)collector circuitc) emitter circuit

8. A resolver hasa) 2 coils on the rotor and 2 coils on the statorb)3 coils on the rotor and 2 coils on the statorc) 2 coils on the rotor and 3 coils on the stator

9. The 'null' point on a control synchro is when the two rotors area) at 90o to each otherb)parallel to each otherc) wired in series

10. A FET when compared to a junction transistor isa) low impedanceb)high impedancec) current operated

1. What type of diode would be used to stop voltage spikes across a coilof a relay?a) Gunn diodeb)Schottky diodec) Double acting diode

2. A silicon diode, when compared to a germanium diode hasa) a higher forward bias voltageb)less forward bias voltagec) the same forward bias voltage

3. A zener diode is used fora) rectificationb)voltage stabilizationc) modulation

4. A multi-layer PCB hasa) one layer on either sideb)two or more layers on one or both sidesc) two or more layers connected in series

5. When a servomotor overshoots after a step input and oscillates it isa) over dampedb)under dampedc) critically damped

6. The rotor of a desynn indicator isa) an electromagnetb)a permanent magnetc) an AC magnet

7. The position feedback from a potentiometer isa) anti-phaseb)in phasec) 90 degrees out of phase

8. A differential synchro hasa) 3 phase stator, 3 phase rotorb)single phase stator, 2 phase rotorc) 3 phase stator, single phase rotor

9. When a servomotor has stopped, the rate feedback from atachogenerator isa) zerob)maximum and in phasec) maximum and anti-phase

10. A tachogenerator is usually used fora) rate feedbackb)angular feedbackc) position feedback

2. Differential synchros havea) a transmitter onlyb)a receiver onlyc) a transmitter and a receiver

3. In an integrated circuit, the components are mounteda) by means of wires connecting themb)by metal oxide filmc) by metal screws

5. One characteristic of the emitter follower isa) low resistance outputb)low current amplificationc) high voltage amplification

6. A reduction from the optimum setting of the velocity feedback in aservo loop could causea) low servo gainb)instabilityc) slow response

7. In a torque synchro system, the power supply is connected toa) the rotor windings of the transmitter onlyb)the rotor windings of both the transmitter and receiverc) the stator windings of the transmitter

8. The phase difference between the supplies of a two phase inductionmotor isa) 180ob)90oc) 0o

9. To reduce overshoot errors in a synchroa) the system will have position feedbackb)the system will have velocity feedbackc) the gain of the amplifier is increased

10. A synchro transformer is used toa) derive an error voltage from a synchro transmitter signal and ashaft positionb)obtain a 26 volt AC referencec) add the output of two synchro transmitters

2. Reversal of the complete power to a torque synchro system willa) have no effectb)cause reverse rotation of the receiver rotorc) displace the receiver rotor by 180o

3. The power supply to a torque synchro system isa) ACb)DCc) AC or DC5. When a positive voltage is applied to the base of a normally biasedn-p-n common emitter amplifiera) the emitter current decreasesb)the collector voltage goes less positivec) the base current decreases

6. An amplifier current gain will be slightly less than 1, but itsvoltage gain will be high, if it is connected in thea) common base configurationb)common emitter configurationc) common collector configuration

7. An open loop system is one which hasa) no direct feedback loopb)rate feedback loopc) position feedback only

Electrics

The DC generator main contactor is welded closed. The fault indicated isa The generator failure warning light illuminatesb The generator ammeter reading is highc# The aircraft generator continues to rotate after the engine is shut down

The DC generator switch directly controls thea Generator fieldb# Generator contactorc Generator warning light

Increasing the load on a permanent magnet generator willa Reduce the terminal voltage by a large amountb# Reduce the terminal voltage by a small amountc Increase the terminal voltage by a small amount

The separately excited generator voltage isa Independent of rotational speedb Controlled by the loadc# Controlled by the separate supply

The series wound generators terminal voltage will, when below saturationa# Increase with an increase in loadb Decrease with an increase in loadc Decrease with a decrease in rotational speed

The shunt wound generator is normally starteda# Off loadb On loadc Either of the above

The shunt wound generator is controlled by a variable resistance ina Series with the armatureb# Series with the fieldc Parallel with the armature

In a cumulative compound wound generator thea The series and shunt fields oppose each otherb# The series and shunt fields assist each otherc Voltage falls suddenly with an increase in load

Which generators are usually used on aircrafta Seriesb# Shuntc Compound

Increasing the speed of an aircraft generator results in an automatica# Field circuit resistance increaseb Field circuit resistance decreasec Armature circuit resistance increase

In the shunt generator the field is supplied bya A separate supplyb# The armaturec The load

The shunt generators voltage falls on load due to thea High resistance of the fieldb Low resistance of the armaturec# Armature volts drop

Which one of the following aircraft cables if heated excessively could give off toxic fumesa Nyvinb Tersilc# Efglas

Which of the following cables is most flexible throughout its temperature rangea# Efglasb Unifire Fc Tersil

Which of the following cables has a conductor of tinned copper strandsa# Nyvinb Tersilc Efglas

A cable is marked Tersil 22 the 22 refers toa The current ratingb# The American wire gauge of the conductorc The current/weight ratio

To measure current in a circuit the ammeter is connecteda In parallel with the loadb# In series with the loadc Across the power supply

The resistance of an ammeter must bea High to create a large volts drop across itb Low because the ammeter is in parallel with the circuitc# Low to prevent volts drop across it

A volt meter may be used in a circuit to measurea EMF of the supply onlyb Volts drop across loads onlyc# Both of the above

To measure voltage in a circuit a voltmeter is connecteda In seriesb# In parallelc Only across the power supply

The resistance of a voltmeter must bea Low to provide a parallel path for the circuit currentb# High so that little current passes through itc Low to prevent overloading the circuit

The forces acting on a meter which moves the pointer over the scale is calleda The controlling forceb The turning forcec# The deflecting force

The force acting on a meter which returns the pointer to zero is called thea# The controlling forceb The turning forcec The deflecting force

The force acting on a meter which opposes the deflecting force is called thea# The controlling forceb The turning forcec The damping force

The damping force in a meter operatesa Only when the pointer is stationaryb# Only when the pointer is movingc At all times whether the pointer is moving or stationary

The damping forcea# Prevents oscillation of the pointerb Assists the pointer to move over the scalec Returns the pointer to zero

In a moving coil meter the deflecting force is provided bya Hairsprings which move the pointer towards full scaleb A soft iron permanent magnetc# A current carrying coil pivoted in a permanent magnet field

In a moving coil meter the deflecting forcea Decreases with an increase of current through the coilb Increases with a decrease of current through the coilc# Increases with an increase of current in the coil

The controlling force in a moving coil meter is afforded bya Single hairspring onlyb Taut bands onlyc# Either hairsprings or taut bands

Hairsprings in a moving coil meter providea# A controlling force and a method of electrical connections to the coilb The deflecting and damping forcec Electrical connections to the coil only

In a moving coil metera The hair springs are permanently attached at both endsb# The outer end of one spring is movable to provide zero adjustmentc The hairsprings are movable at both ends to provide full scale and zero adjustments

In a moving coil meter damping is provided bya# Electromagnetic induction in the coil frameb An air or oil dashpotc By a system of levers

When using a moving coil meter to measure current, as an ammeter it is usual toa Connect a very high resistor in parallel with the coilb# Connect a very low resistor in parallel with the coilc Connect a very high resistor in series with the coil

The resistor used to extend the range of an ammeter is called aa Variacb# Shuntc 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 isa# 1 ohm approx.b 99 ohm approx.c 100 ohm approx.

An external resistor used to extend the range of an ammeter usually hasa Two connections onlyb Two voltage connections and one voltage connectionsc# 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 witha The value of the resistor in ohmsb# Fullscale current and millivolts dropc 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 froma# 0-100mVb 0-1Vc 0-100v

The resistor used to extend the range of a moving coil voltmeter is called aa Variacb Shuntc# Multiplier

The resistor used to extend the range of a moving coil voltmeter is placeda In parallel with the coilb In series with the loadc# 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 isa 990 ohmsb# 9900 ohmsc 9990 ohms

The differential cutout contacts are closed using thea# Voltage coil onlyb Current coil onlyc Both voltage and current coils

The indication of a short circuit in the remote ammeter shunt is that thea Generator fails to come onlineb Generator failure warning light remains onc# Generator operates normally but the ammeter reads zero

With a rising generator voltage in a DC generation system thea# Undervolts relay closes before the differential relayb Differential relay closes before the undervolts relayc Undervolts and differential relays operate independently1. 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 byD.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.