04 Electronics V

JAR 66 Module 1 Exam Practice ExamModule 4

This is exam number 1.

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

2. A germanium diode is used fora) rectificationb)voltage stabilizationc) modulationAnswer:a

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 voltageAnswer:a

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 placedAnswer:b

5. In an NPN transistor the P is thea) collectorb)basec) emitterAnswer:b

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

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

8. This is a diagram of

a) a TRIACb)an SCRc) a Schottky diodeAnswer:b

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

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

Answer:c


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

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 usedAnswer:a

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 impedanceAnswer:c

4. How is the amplifier in the diagram shown wired?

a) Common baseb)Common emitterc) Common collectorAnswer:b

5. What gate does the following Boolean expression representF = A.B.Ca) ANDb)ORc) NOTAnswer:a

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

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

8. A resolver has

a) 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 statorAnswer:a

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 seriesAnswer:a

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


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

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

3. A zener diode is used fora) rectificationb)voltage stabilization

c) modulationAnswer:b

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 seriesAnswer:a

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

6. The rotor of a desynn indicator isa) an electromagnetb)a permanent magnetc) an AC magnetAnswer:b

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

8. A differential synchro hasa) 3 phase stator, 3 phase rotorb)single phase stator, 2 phase rotorc) 3 phase stator, single phase rotorAnswer:a

9. When a servomotor has stopped, the rate feedback from a

tachogenerator isa) zerob)maximum and in phasec) maximum and anti-phaseAnswer:a

10. A tachogenerator is usually used fora) rate feedbackb)angular feedbackc) position feedbackAnswer:a


1. What is this circuit?

a) Half wave rectifierb)Full wave rectifierc) Flywheel diodeAnswer:a

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

3. In an integrated circuit, the components are mounted

a) by means of wires connecting themb)by metal oxide filmc) by metal screwsAnswer:b

4. This symbol is

a) a diodeb)a triac

c) a transistorAnswer:a

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

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

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 receiver

c) the stator windings of the transmitterAnswer:b

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

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 increasedAnswer:b

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 transmittersAnswer:a


1. This is a diagram of a

a) differentiatorb)integratorc) adderAnswer:a

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 180oAnswer:a

3. The power supply to a torque synchro system isa) ACb)DCc) AC or DCAnswer:a

4. This symbol is

a) an LEDb)a laser diodec) a photodiodeAnswer:c

5. 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 decreasesAnswer:b

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 configurationAnswer:a

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

c) position feedback onlyAnswer:a

8. Mechanical friction in a servo results ina) reduced gainb)increased dampingc) increased inertiaAnswer:b

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 signalAnswer:b

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


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

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 windingsAnswer:c

3. This is a diagram of a

a) differentiatorb)integratorc) adderAnswer:b

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

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 voltageAnswer:b

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

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

Answer:a

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

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 positionAnswer:b

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

Answer:c


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 onlyAnswer:c

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

Answer:c

3. What is a shottky diode used for?a) Very high frequency applicationsb)Stabilsationc) RectificationAnswer:a

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 anticlockwiseAnswer:c

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

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 rotorsAnswer:b

7. A differential synchro rotor has

a) three windingsb)two windings

c) one windingAnswer:a

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

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 180oAnswer:c

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 nullAnswer:c


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 dischargeAnswer:b

2. An amplifier can provide both voltage gain and current gain when itis connected in the

a) common base configurationb)common emitter configurationc) common collector configurationAnswer:b

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

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

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 runawayAnswer:b

6. A resolver synchro output is obtained from a rotor witha) one single coilb)three coils at 120oc) two coils at 90oAnswer:c

7. In a control synchro the stator current ceases to flow whena) the CT rotor is at null

b)when the two rotors are alignedc) when power is removedAnswer:c

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 speedAnswer:c

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 180oAnswer:c

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


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 barrierAnswer:c

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 dotAnswer:a

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

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

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

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 voltageAnswer:b

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

Answer:a

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 otherAnswer:a

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 inputAnswer:c

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


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

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

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

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 moveAnswer:b

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

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 theservomechanismAnswer:b

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

c) transmitter and receiver rotorsAnswer:a

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 linesAnswer:a

9. Velocity feedbacka) opposes the demand inputb)assists the demand inputc) prevents dead space errorsAnswer:a

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

Answer:c

exam number 11.

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 rotor

a) 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

Answer

1. 2 3 4 5 6 7 8 9 10C A C B B C C A B A


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 system

b)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

Answer

1. 2 3 4 5 6 7 8 9 10B C B C B B A A B B


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 important

c) 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 of

a) one winding parallel to the transmitter rotorb)two windings at 90o apartc) three windings at 120o apart

Answer

1. 2 3 4 5 6 7 8 9 10C C C C A B A C C C


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

7. What is resistor R used for?

a) Amplificationb)Biasc) Stabilisation

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

Answer

1. 2 3 4 5 6 7 8 9 10C A A C B B C C A B


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 magnet

c) 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

Answer

1. 2 3 4 5 6 7 8 9 10B C B Cx B B A A C C


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

Answer

1. 2 3 4 5 6 7 8 9 10C A B A A C B B B B


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 gain

b)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

Answer

1. 2 3 4 5 6 7 8 9 10

A B B A B C A A C B

This is exam number 18. Exam !8

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

2. What does the circuit shown below do?

a) Full wave rectifierb)Voltage doublerc) Half wave rectifier

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 called

a) 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

Answer

1. 2 3 4 5 6 7 8 9 10B C A A A C A A A A


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 for

a) 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 is

a) 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

Answer

1. 2 3 4 5 6 7 8 9 10C C C C C C C A C C


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 off

a) 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

8.This is a diagram of

a) an SCRb)a transistor

c) a photo diode

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

Answer

1. 2 3 4 5 6 7 8 9 10A B B B A A A C B C


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 Cathode

b)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

Answer

1. 2 3 4 5 6 7 8 9 10A C B A A B C B B C

This is exam number 22

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 0

b)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

Answer

1. 2 3 4 5 6 7 8 9 10A B A B A C B A B B


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

Answer

1. 2 3 4 5 6 7 8 9 10B B B A B A C A A A


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 so

thata) 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

Answer

1. 2 3 4 5 6 7 8 9 10A B B B A A B C A B


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 force

b)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 effectAnswer

1. 2 3 4 5 6 7 8 9 10B B B B A B B C C A


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 should

bea) 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) 2V

b)4Vc) 6V

Answer

1. 2 3 4 5 6 7 8 9 10C C B A A B C A C A


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

5.Point X compared to point

a) Z is more positiveb)Y is more negativec) Z is more negative

6.The typical bandwidth for an audio frequency amplifier is shown by line

a) Xb)Yc) Z

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

8. Increasing velocity feedback from optimum will givea) sluggish performance

b)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

Answer

1. 2 3 4 5 6 7 8 9 10B C C B A A B A A B


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) neutral

b)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 rotateAnswer

1. 2 3 4 5 6 7 8 9 10C A A A C B A A B B


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

Answer

1. 2 3 4 5 6 7 8 9 10B B A A B B A A A A


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 amplifier

b)voltage amplifierc) both

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

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

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 sameAnswer

1. 2 3 4 5 6 7 8 9 10C A C A C B A A C B


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

2.In the above diagram the phase of the input to the output is

a) in phaseb)180 degrees out of phasec) 90 degrees out of phase

3.The above diagram shows a

a) voltage doublerb)half wave rectifierc) full wave rectifier

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) CAnswer

1. 2 3 4 5 6 7 8 9 10C B A A C A B A A A


1.Under normal operating conditions X will be

a) negative with respect to Zb)positive with respect to Zc) negative with respect to Y

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

4. In which direction does the current flow on a PNP transistor whenforward biased?a) Emitter to collectorb)Collector to emitterc) Emitter to base

5. What does a resolver do?a) Resolves a position into sine and cosine componentsb)Adds two signalsc) Resolves a movement into sine and cosine components

6. What component is used to turn AC to DC?a) Diodeb)Transistorc) Thyristor

7. What is an intrinsic material?a) One with removed elementsb)One with added elementsc) A pure material

8. What does the colour of an LED depend upon?a) Materialb)Voltagec) Current

9. In an electronic circuit, if the anode of a diode is clamped toground what is this called?a) A high level clampb)A low level clamping circuitc) A negative limiting circuit

10. If the feedback is ideal damped, the signal will

a) overshoots once and return backb)oscillatec) not overshoot

Answer

1. 2 3 4 5 6 7 8 9 10B A A A A A C A A A


1. The voltage drop of silicon diode isa) 0.3 Vb)0.7 Vc) 1 V

2. The negative feedback for integrator is connected across aa) resistorb)capacitorc) inductor

3. To decrease the capacitance of a varactora) forward bias should be increasedb)reverse bias should be decreasedc) reverse bias should be increased

4. In a printed board circuit, the surface resistance testing isa) the resistance between the tow inductorsb)insulation resistance between adjacent printed conductorc) between the board and the conductor.

5. A Zener diode is used across the output for a power supply circuit toa) give a full wave rectification

b)provide a steady DC voltage output without fallingc) prevent thermal runway

6. If a diode has gone open circuit in a full wave bridge rectifier, theoutput frequency ripple isa) the same input frequencyb)twice the input frequencyc) half the input frequency

7. In a tachogenerator the output voltage isa) inversely proportional to the speedb)directly proportional to the speedc) zero

Answer

1. 2 3 4 5 6 7 8 9 10B B C B B C B

8.a)b)c)

9.a)b)

c)

10.a)b)c)

c

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