JAR part 66 examination mod 04

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JAR 66 Module 1 Exam Practice Exam Module 4

This is exam number 1. 1. What gives the colour of an LED? a) The plastic it is encased in b)The active element c) The type of gas used inside it Answer:b 2. A germanium diode is used for a) rectification b)voltage stabilization c) modulation Answer:a 3. Why is a diode put in parallel with an LED? a) To protect it from AC b)So it will work only above a certain voltage c) So it will work only below a certain voltage Answer:a 4. When testing the forward bias of a diode with a multimeter a) the positive lead of the ohmeter is placed on the cathode b)the positive lead of the ohmeter is placed on the anode c) it does not matter which terminal the positive lead of the ohmeter is placed Answer:b

5. In an NPN transistor the P is the a) collector b)base c) emitter Answer:b

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6. The output of a tachogenerator is a) proportional to speed of rotation b)proportional to position c) proportional to acceleration Answer: 7. AC power is supplied to a) torque receiver only b)torque transmitter only c) both the torque receiver and torque transmitter Answer:c 8. This is a diagram of

a) a TRIAC b)an SCR c) a Schottky diode Answer:b 9. How is a PCB protected after manufacture? a) With non-conductive varnish b)With wax c) By conformal coating Answer:c 10. A differential synchro a) can only be used as a transmitter b)can only be used as a receiver c) can be used as either a transmitter or a receiver

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Answer:c This is exam number 2. 1. Which of the following describes the characteristics of a Thyristor? a) High voltage handling b)High current handling c) High power handling Answer:b 2. A semiconductor doped with an element having a valency of 5 will produce a) an N type material b)a P type material c) either an N type or a P type depending on what type of semiconductor material is used Answer:a 3. What are the ideal characteristics of an Op Amp? a) Infinite gain, infinite input Impedance and infinite output impedance b)Low gain, infinite input Impedance and zero output impedance c) Infinite gain, infinite input Impedance and zero output impedance Answer:c

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

a) Common base b)Common emitter c) Common collector Answer:b 5. What gate does the following Boolean expression represent F = A.B.C a) AND b)OR c) NOT Answer:a 6. What gate does the following Boolean expression represent F = A+B+C a) NOT b)NOR c) OR Answer:c 7. To decrease the voltage gain of a common emitter amplifier you would increase the resistance in the a) base circuit b)collector circuit c) emitter circuit Answer:b 8. A resolver has

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a) 2 coils on the rotor and 2 coils on the stator b)3 coils on the rotor and 2 coils on the stator c) 2 coils on the rotor and 3 coils on the stator Answer:a 9. The 'null' point on a control synchro is when the two rotors are a) at 90o to each other b)parallel to each other c) wired in series Answer:a 10. A FET when compared to a junction transistor is a) low impedance b)high impedance c) current operated Answer:b This is exam number 3. 1. What type of diode would be used to stop voltage spikes across a coil of a relay? a) Gunn diode b)Schottky diode c) Double acting diode Answer:c 2. A silicon diode, when compared to a germanium diode has a) a higher forward bias voltage b)less forward bias voltage c) the same forward bias voltage Answer:a 3. A zener diode is used for a) rectification b)voltage stabilization

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c) modulation Answer:b 4. A multi-layer PCB has a) one layer on either side b)two or more layers on one or both sides c) two or more layers connected in series Answer:a 5. When a servomotor overshoots after a step input and oscillates it is a) over damped b)under damped c) critically damped Answer:b 6. The rotor of a desynn indicator is a) an electromagnet b)a permanent magnet c) an AC magnet Answer:b 7. The position feedback from a potentiometer is a) anti-phase b)in phase c) 90 degrees out of phase Answer:a 8. A differential synchro has a) 3 phase stator, 3 phase rotor b)single phase stator, 2 phase rotor c) 3 phase stator, single phase rotor Answer:a 9. When a servomotor has stopped, the rate feedback from a

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tachogenerator is a) zero b)maximum and in phase c) maximum and anti-phase Answer:a 10. A tachogenerator is usually used for a) rate feedback b)angular feedback c) position feedback Answer:a This is exam number 4. 1. What is this circuit?

a) Half wave rectifier b)Full wave rectifier c) Flywheel diode Answer:a 2. Differential synchros have a) a transmitter only b)a receiver only c) a transmitter and a receiver Answer:c 3. In an integrated circuit, the components are mounted

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a) by means of wires connecting them b)by metal oxide film c) by metal screws Answer:b 4. This symbol is

a) a diode b)a triac c) a transistor Answer:a 5. One characteristic of the emitter follower is a) low resistance output b)low current amplification c) high voltage amplification Answer:a 6. A reduction from the optimum setting of the velocity feedback in a servo loop could cause a) low servo gain b)instability c) slow response Answer:b 7. In a torque synchro system, the power supply is connected to a) the rotor windings of the transmitter only b)the rotor windings of both the transmitter and receiver

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c) the stator windings of the transmitter Answer:b 8. The phase difference between the supplies of a two phase induction motor is a) 180o b)90o c) 0o Answer:b 9. To reduce overshoot errors in a synchro a) the system will have position feedback b)the system will have velocity feedback c) the gain of the amplifier is increased Answer:b 10. A synchro transformer is used to a) derive an error voltage from a synchro transmitter signal and a shaft position b)obtain a 26 volt AC reference c) add the output of two synchro transmitters Answer:a

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This is exam number 5. 1. This is a diagram of a

a) differentiator b)integrator c) adder Answer:a 2. Reversal of the complete power to a torque synchro system will a) have no effect b)cause reverse rotation of the receiver rotor c) displace the receiver rotor by 180o Answer:a 3. The power supply to a torque synchro system is a) AC b)DC c) AC or DC Answer:a

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4. This symbol is

a) an LED b)a laser diode c) a photodiode Answer:c 5. When a positive voltage is applied to the base of a normally biased n-p-n common emitter amplifier a) the emitter current decreases b)the collector voltage goes less positive c) the base current decreases Answer:b 6. An amplifier current gain will be slightly less than 1, but its voltage gain will be high, if it is connected in the a) common base configuration b)common emitter configuration c) common collector configuration Answer:a 7. An open loop system is one which has a) no direct feedback loop b)rate feedback loop

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c) position feedback only Answer:a 8. Mechanical friction in a servo results in a) reduced gain b)increased damping c) increased inertia Answer:b 9. The position feedback signal is a) in phase with the input demand signal b)in anti-phase with the demand signal c) phase advanced by 90o with respect to the input signal Answer:b 10. A servo system that overshoots and oscillates is a) under damped b)over damped c) critically damped Answer:a This is exam number 6. 1. The power supply to a torque synchro system is connected to a) the transmitter stator b)the transmitter rotor only c) the transmitter and receiver rotors Answer:c 2. If the rotor of the receiver in a torque synchro system was prevented from aligning with the transmitter rotor, then a) the transmitter rotor will turn to align with the receiver rotor b)the receiver will overheat c) a high current will flow in the stator windings Answer:c

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3. This is a diagram of a

a) differentiator b)integrator c) adder Answer:b 4. A zener diode a) stabilizes voltage at a predetermined level b)allows current to flow in one direction c) acts like a switch Answer:a 5. The common collector amplifier is sometimes called the emitter follower circuit because a) the emitter current follows the collector current b)the emitter voltage follows the base voltage c) the emitter voltage follows the collector voltage Answer:b 6. In a toroidal resistance transmitter indicator system, the power supply is connected to a) the brushes b)the resistor slab c) the rotor Answer:a 7. When a servo has reached its null and stopped, the velocity feedback is a) zero b)maximum and anti-phase c) maximum and in phase

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Answer:a 8. The primary purpose of rate feedback in a positional servo system is to a) ensure minimum response time b)prevent excessive overshoot c) ensure system linearity Answer:b 9. In an AC rate servo, a steady input will result in the servomotor a) oscillating about a new datum b)rotating at a constant speed c) rotating to a new datum position Answer:b 10. An E&I bar output at datum has a) no induced voltage in the secondary windings b)an imbalance of voltages in the secondary windings c) equal and opposite voltages induced in the secondary Answer:c This is exam number 7. 1. A non-inverting op-amp a) has a non-inverting input and an inverting output b)has an inverting input and a non-inverting output c) a non-inverting input connection only Answer:c 2. Amplifiers may be classified as a) common emitter or common collector amplifiers b)voltage amplifiers or impedance amplifiers c) voltage amplifiers or power amplifiers

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Answer:c 3. What is a shottky diode used for? a) Very high frequency applications b)Stabilsation c) Rectification Answer: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 60o clockwise would be a) the receiver would move 60o clockwise b)the receiver would move 120o anticlockwise c) the receiver would move 60o anticlockwise Answer:c 5. The control windings of a two phase servomotor is supplied with AC voltage of a) constant amplitude b)variable phase c) variable amplitude, variable phase Answer:c 6. In a torque synchro that includes a differential synchro the power supply is connected to a) the transmitter rotor only b)the transmitter and receiver rotors only c) all three rotors Answer:b 7. A differential synchro rotor has a) three windings b)two windings

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c) one winding Answer:a 8. If the rotor of a control synchro sticks a) the system hunts b)high current will flow c) the position feedback will oscillate Answer:b 9. With the reversal of the connections to the rotor of the transmitter of a torque synchro, the position of the receiver rotor will be a) unchanged b)changed by 120o c) changed by 180o Answer:c 10. The application of a 'stick-off' voltage to a control synchro servo system is a) to overcome the effect of static friction b)to overcome the effect of viscous friction c) to prevent alignment to a false null Answer:c This is exam number 8. 1. When removing a microprocessor a) no damage is done by static discharge b)considerable damage can be done by static discharge c) ensure the power is OFF to avoid static discharge Answer:b 2. An amplifier can provide both voltage gain and current gain when it is connected in the

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a) common base configuration b)common emitter configuration c) common collector configuration Answer:b 3. How do you increase voltage gain of an amplifier? a) decrease base circuit bias b)decrease input resistance c) increase input resistance Answer:b 4. In a resolver synchro the stator windings are electrically displaced by a) 90o b)120o c) 180o Answer:a 5. A servo system may include a brake, an automatic trim system is one example where a brake is used. The brake is a) applied during trimming to prevent oscillations about the demand position b)applied when trimming is complete to prevent stabilizer creep c) applied during trimming to prevent servo runaway Answer:b 6. A resolver synchro output is obtained from a rotor with a) one single coil b)three coils at 120o c) two coils at 90o Answer:c 7. In a control synchro the stator current ceases to flow when a) the CT rotor is at null

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b)when the two rotors are aligned c) when power is removed Answer:c 8. In a speed control servo system (rate control), the purpose of the tachogenerator is a) to make the velocity proportional to servo demand b)to make the deflection proportional to servo demand c) to make it run at constant speed Answer:c 9. The result of reversing the rotor connections to the receiver of a torque synchro system is that the rotor position a) is unchanged b)is changed by 120o c) is changed by 180o Answer:c 10. The rotor of a torque synchro indicator is a) supplied with an excitation voltage b)short circuited c) connected in series with the transmitter stator coil Answer:a This is exam number 9. 1. When a hole diffuses from a p-region to the n-region it a) becomes a minority carrier in the n-region b)lowers the potential barrier c) raises the potential barrier Answer:c

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2. How are the pins numbered on an op-amp IC? a) counter clockwise from the dot b)clockwise from the dot c) from left to right from the dot Answer:a 3. To increase the output of a servo amplifier, it is necessary to a) reduce the tacho feedback b)increase the tacho feedback c) increase the position feedback Answer:a 4. Angular displacement of the control coils with respect to the reference coils in a two phase induction motor are a) 0o, 180o b)90o, 270o c) 90o, 120o Answer:b 5. a two phase induction motor used in a servomechanism a) will always require a starter b)is self starting under light loads c) runs with no slip Answer:b 6. A servomotor having only a tachogenerator as a feedback device will a) vary its speed with input error voltage b)have a constant speed for any given input voltage c) null out at a position dependant upon input error voltage Answer:b 7. A hysteresis servo motor is used in a servomechanism because a) it has good starting characteristics b)good speed/voltage relationship c) low inertia

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Answer:a 8. The null position of a torque synchro system is when a) the TX and TR rotors are parallel to each other b)the TX and TR rotors are 90o to each other c) the TX and TR rotors are 120o to each other Answer:a 9. Reversal of two of the stator connections on a torque synchro receiver would cause a) the transmitter to become the receiver b)the output to move the same direction as the input c) the output to move the reverse direction to the input Answer:c 10. An AC tachogenerator stator has a) two windings 180o apart b)three windings 120o apart c) two windings 90o apart Answer:c This is exam number 10. 1. A junction diode a) has one p-n junction b)is similar to a vacuum diode but cannot rectify c) can handle only very small currents Answer:a

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2. When the rotor of an AC tachogenerator is stationary, the rotor has a) no circulating currents b)low circulating currents c) no magnetic fields Answer:b 3. The output of a tachogenerator should be a) sinusoidal b)exponential c) linear Answer:a 4. With a constant input to a speed control servo, the servo motor a) moves to a certain position b)moves at a constant speed c) oscillates, but otherwise does not move Answer:b 5. A closed loop servomechanism a) must only have position feedback b)must have both position and velocity feedback c) can have either position or velocity feedback Answer:c 6. Critical damping in a servomechanism is a) the point which allows just one overshoot before the load comes to rest b)the amount of damping that results in the load just not oscillating c) the critical damping required for the optimum damping of the servomechanism Answer:b 7. In a control synchro system the power supply is connected to the a) transmitter rotor and amplifier b)receiver rotor and amplifier

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c) transmitter and receiver rotors Answer:a 8. Reverse rotation of a control transformer rotor can be caused by a) connections between the transformer rotor and the amplifier reversed b)connections to the transmitter rotor reversed c) short circuit between two transmission lines Answer:a 9. Velocity feedback a) opposes the demand input b)assists the demand input c) prevents dead space errors Answer:a 10. Velocity lag can be decreased by a) introduction of an integrator b)keeping the error detector (summing point) output as low as possible c) decreasing the coulomb friction in the system Answer:c exam number 11. 1. The junction barrier offers opposition to only a) holes in the p-region b)free electrons in the n-region c) majority carriers in both regions 2. An increase in velocity feedback will a) decrease the speed the load moves b)increase the speed the load moves c) have no effect on speed

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3. A two phase motor will stop when a) the reference phase is reversed b)the control phase is reversed c) the control phase is zero 4. A tachogenerator output is a) variable frequency, constant voltage b)variable voltage, constant frequency c) variable frequency, variable voltage 5. Rate feedback can be obtained from a a) synchro b)tachogenerator c) potentiometer 6. Positional feedback can be obtained from a a) synchro b)tachogenerator c) potentiometer 7. The frictional force in a servomechanism that is proportional to speed is called a) stiction b)coulomb friction c) viscous friction 8. The 'null' point in a control synchro is when the two rotors are a) at 90o to each other b)parallel to each other c) wired in series 9. If two of the stator leads are cross connected in a control synchro system, a 25o clockwise rotation of the input rotor would result in the output rotor

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a) moving 25o clockwise b)moving 25o anticlockwise c) moving 180o to rectify the defect 10. Damping in a servomechanism is easier to apply if a) the mechanism is light and has low inertia b)the mechanism is heavy and has high inertia c) the mechanism is light and has high inertia Answer 1. 2 3 4 5 6 7 8 9 10C A C B B C C A B A � This is exam number 12. 1. Reverse bias a) lowers the potential barrier b)raises the potential barrier c) greatly increases the majority carrier current 2. If the electrical connections to the feedback generator in a control synchro system were disconnected, the a) motor would run in the wrong direction b)input signal to the amplifier would reduce c) system would tend to oscillate 3. An increase in servo amplifier gain a) reduces the speed of the system

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b)increases system response c) reduces tendency to hunt 4. In a control synchro the stator current ceases to flow when the a) CT rotor is at null b)two rotors are aligned c) power is removed 5. The term 'velocity lag' refers to a a) speed error b)position error c) acceleration error 6. The rotor of an AC tachogenerator a) has skewed slots b)has a copper, brass or aluminium cylinder c) rotates at constant speed 7. A servo system with transient negative velocity feedback a) is damped with little velocity lag b)is damped with high velocity lag c) is underdamped with high velocity lag 8. To reverse the direction of rotation of a two phase induction motor a) reverse the polarity of the control phase b)reverse the polarity of both the control phase and reference phase c) shift the reference by 90o 9. In a rate servo (speed control) the signal into the servo amplifier is a) input voltage plus tachogenerator output b)input voltage minus tachogenerator output c) input voltage plus position feedback voltage

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10. Loss of DC to a servo amplifier causes the motor to a) run continuously b)stop c) reverse Answer 1. 2 3 4 5 6 7 8 9 10 B C B C B B A A B B This is exam number 13. 1. Avalanche breakdown occurs when a) forward current becomes excessive b)forward bias exceeds a certain value c) reverse bias exceeds a certain value 2. An AC servo demand can be converted to drive a DC motor by the introduction of a a) rectifier b)modulator c) demodulator 3. Synchro indicator systems are used when the indication is required to move a) a fraction of the input distance b)slower than the input rate c) at the same rate as the input 4. A linear variable differential transformer is used to measure position feedback where a) 360o of rotation and high angular accuracy is required b)accuracy is of limited importance but robust construction and reliability is important

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c) an output whose phase is related to direction of movement and amplitude linear over a wide range 5. A low frequency sinusoidal input will cause a closed loop servomechanism load to a) move to a demand position with no overshoot b)move backwards and forwards at the input frequency c) move to the demand position and then return to the datum position without any overshoot 6. To reduce oscillations about a demand position a) the amount of velocity feedback would be decreased b)the amount of velocity feedback would be increased c) the amount of position feedback would be increased 7. If a servo amplifier is suffering from drift a) the load would move to a new position, proportional to the drift and stay there b)the load would move to a new position, proportional to the drift and then return back to the datum position c) the load would oscillate about the datum position 8. In a transient velocity feedback circuit, the tachogenerator output is summated with the demand voltage a) only when the load is slowing down b)at all times when the load is moving c) only when the load is speeding up or slowing down 9. Positive feedback applied to a servomechanism a) decreases the response of the system b)opposes the demand signal c) increases the response of the system 10. A differential synchro rotor consists of

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a) one winding parallel to the transmitter rotor b)two windings at 90o apart c) three windings at 120o apart Answer 1. 2 3 4 5 6 7 8 9 10 C C C C A B A C C C This is exam number 14. 1. A differential synchro transmitter used for addition has a) the TDX S1 and S3 connections cross connected to the TX b)the TDX S1 and S3 connections cross connected to the TR c) the TDX R1, R3 and S1, S3 connections cross connected to the TX 2. If forward bias is increased from zero on a p-n junction, a rapid increase in current flow for a relatively small increase in voltage occurs a) only after the forward bias exceeds the potential barrier b)when the flow of minority carriers is sufficient to cause an avalanche breakdown c) when the depletion layer becomes larger than the space charge area 3. An LVDT has a) an output winding which is wound in series opposition b)an input winding whose voltage will change with load movement c) an output winding whose voltage and frequency is linear to load angular movement 4. A diode connected across a relay coil is used to a) allow the coil to energize with only one polarity b)cause a delay in switching on c) dissipate coil spikes on switch off

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5. Differential transmitters are used to a) add or subtract two electrical signals b)add or subtract a mechanical signal to an electrical synchro signal c) increase the operating speed of the synchro receiver 6. To convert a differential synchro from subtraction to addition you would a) reverse the reference phase supply b)change over two rotor and stator connections c) change over all three stator windings 7. What is resistor R used for?

a) Amplification b)Bias c) Stabilisation 8. When resolving a Cartesian input to a Polar output a) the inputs are a shaft angle and a voltage b)the outputs are two voltages c) the inputs are two voltages 9. To check the forward resistance of a diode with a multimeter, the lead connected to the positive terminal is put to the a) anode b)cathode c) either anode or cathode

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10. A resolver synchro output is obtained from a rotor with a) one single coil b)two coils at 90o to each other c) three coils at 120o to each other Answer 1. 2 3 4 5 6 7 8 9 10 C A A C B B C C A B This is exam number 15. 1. The input and output signals of a common emitter amplifier are a) equal b)out of phase c) in phase 2. The output of a resolver synchro is a) dependant upon the position of the rotor only b)proportional to the speed of input rotation c) a function of the rotor position and excitation voltage 3. The rotor of an autosyn position indicating system is a) a permanent magnet b)an electromagnet c) spring controlled 4. A band pass filter excludes frequencies a) above the frequency required only b)below the frequency required only c) above and below the frequency required 5. The rotor of a magnesyn transmitter is a) a dc electromagnet b)a permanent magnet

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c) an ac electromagnet 6. In general the accuracy of a synchro system increases if the a) stator current is high b)stator current is low c) rotor current is high 7. Torque synchro systems are normally used when the a) mechanical load is low b)mechanical load is high c) system accuracy is of extreme importance 8. In a resolver synchro the stator windings are electrically disposed by a) 90o b)120o c) 180o 9. The induced signal in the output coils of the magnesyn system a) de-saturates the soft iron core b)damps the pointer oscillations c) is of a value of 800 Hz 10. The direction of the induced (secondary) magnetic field in a synchro transmitter a) is 90o to the primary magnetic field b)in the same direction as the primary field c) is in the opposite direction to the primary field Answer 1. 2 3 4 5 6 7 8 9 10 B C B Cx B B A A C C

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This is exam number 16. 1. The cogging effect in synchros is rectified by a) using carbon brushes b)using an elliptical cog c) skewing the rotor 2. A transistor is said to be in the quiescent state when a) no signal is applied to the input b)it is unbiased c) no currents are flowing 3. In an unbiased p-n junction, current flow is a) due to the diffusion of minority carriers only b)zero, because no charges are crossing the junction c) zero, because equal but opposite currents are crossing the junction 4. Reversal of the power supply to either the transmitter or the receiver of a torque synchro system would a) cause a 180o displacement between the transmitter and the receiver b)have no effect on the indication, but would cause a heavy current to flow c) make the receiver rotor rotate in the opposite direction 5. Torque synchro systems are normally used when the a) mechanical load is low b)mechanical load is high c) system accuracy is of extreme importance

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6. A common base transistor circuit is so called because a) the base region is located between the emitter and collector region b)the base is n-type material c) the base is common to the emitter and collector circuits 7. What device transfers one energy type to another? a) Transmitter b)Transducer c) Transponder 8. Which way does conventional current flow in a PNP junction? a) Collector to emitter b)Emitter to base c) Collector to base 9. Electrical power is supplied to a synchro rotor a) directly b)through slip rings c) through a commutator 10. The purpose of a flywheel incorporated in a synchro is to a) increase the driving force b)prevent oscillations c) prevent insect ingress Answer 1. 2 3 4 5 6 7 8 9 10 C A B A A C B B B B

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This is exam number 17. 1. In an operational amplifier, the two input waves are the same amplitude, same frequency, but exactly anti-phase. What would the output be? a) Double b)Zero c) Half 2. A thyristor has which of the following? a) High resistance when switched on b)High resistance when switched off c) A positive temperature coefficient 3. On an integrated circuit the hole in the top left corner is pin 1. The pins are counted a) clockwise b)anticlockwise c) from left to right 4. With reference to the circuit shown below, how is the transistor configured? a) Common emitter b)Common collector c) Common base 5. In the circuit diagram above, R1 and R2 are used to a) set the transistor gain

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b)set the DC bias level c) increase the base voltage 6. In a synchro system, if two stator lines are crossed the receiver will a) not be affected b)be 180o out c) reverse direction 7. In the following Boolean algebra statement, which gate is described? F = A + B + C a) Or b)Not c) And 8. In an E and I signal generator at datum, the voltage on the secondary windings a) are equal and opposite b)is maximum c) is zero 9. In a synchro resolver, the stator coils are at what angle in relation to one another? a) 45 degrees b)80 degrees c) 90 degrees 10. In a synchrotel, the a) rotor coil is fixed and the stator coil moves b)rotor coil and stator coil is fixed c) stator coil is fixed and the rotor coil moves Answer 1. 2 3 4 5 6 7 8 9 10

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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 transient currents between which points? a) The electronic circuit and the aircraft ground b)Interspaced along the circuit c) The negative rail and the rest of the circuit 2. What does the circuit shown below do?

a) Full wave rectifier b)Voltage doubler c) Half wave rectifier 3. In an LED, what is used to make the colour? a) The doping material b)The electrons c) The plastic lens cover 4. An atom with 5 electrons in its outer shell is part of a) an N type material b)a P type material c) a C type material 5. In a FET, the junction connections are called

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a) drain, source and gate b)base, collector and emitter c) drain, collector and junctions 6. In the Boolean algebra statement below, the gate described is F = A.B.C a) Nand b)Nor c) And 7. With a small amplitude voltage, what type of diode would you use to produce the output waveform?

a) Shottky b)Gunn c) Zener 8. An increase in negative feedback to the servo amplifier a) increases amplifier stability b)decreases amplifier stability c) has no effect 9. How is a push-pull transistor arrangement connected? a) emitter to emitter b)collector to collector c) base to base

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10. Thermal runaway in a transistor is caused by a) excessive heat causing maximum current flow b)excessive heat causing minimum current flow c) low heat causing minimum current flow Answer 1. 2 3 4 5 6 7 8 9 10 B C A A A C A A A A This is exam number 19. 1. A single integrated circuit Op Amp has how many pins? a) 4 b)7 c) 8 2. What is the output of the amplifier shown below? a) 0V b)3V c) 5V

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3. A thyristor is commonly used for

a) voltage regulation b)overvolts regulation c) rectification 4. A diode which emits photons when conducting is a a) zener b)varactor c) light emitting 5. Avalanche breakdown occurs when a) forward bias becomes excessive b)forward bias exceeds a certain value c) reverse bias exceeds a certain value 6. The electrodes of an SCR are a) anode, cathode, source b)source, drain, gate c) gate, cathode, anode 7. What gives an LED its colour? a) A gas b)The cover c) Composition and impurity of the compound

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8. For conduction of a transistor the emitter junction is a) fwd biased b)reverse biased c) fwd or reverse as appropriate to the input signal 9. In a PNP transistor which way does conventional current flow a) base to emitter b)collector to emitter c) emitter to collector 10. Infinite gain, infinite input impedance & zero output impedance is characteristic of a a) Class A amp b)Class B amp c) Op amp Answer 1. 2 3 4 5 6 7 8 9 10 C C C C C C C A C C This is exam number 20. 1. Forward voltage of a silicon diode is a) 0.6V b)0.2V c) 1.6V 2. An advantage of a common emitter is a) it is a voltage follower b)it has high power gain c) it has high voltage gain

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3. What amplifier is biased at cut off a) A b)B c) C 4. When testing a transistor with an ohmmeter, what is the resistance of the emitter/collector? a) High resistance one way b)High resistance both ways c) Low resistance both ways 5. What is the typical volts drop across an LED a) 1.6V b)0.2V c) 0.4V 6. What diode gives off light photons when forward biased a) LED b)Shottky diode c) Gunn diode 7. A logic circuit with more than one gate will have a) one of 2 states of logic output b)2 or more outputs c) an analogue output 8. This is a diagram of

a) an SCR

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b)a transistor c) a photo diode 9. In a synchro, what is used to convert signals from one form to another? a) Transmitter b)Transducer c) Transformer 10. Components on an integrated circuit are a) in the solid b)don't need them c) on the surface Answer 1. 2 3 4 5 6 7 8 9 10 A B B B A A A C B C This is exam number 21. 1. What diode is used to stop power spikes in a coil? a) Two directional zener diode b)Shottky diode c) Gunn diode 2. The anode of a diode is connected to a +4v DC supply and the cathode is connected to a +2v DC supply. The diode is a) forward biased not conducting b)reverse biased not conducting c) forward biased conducting 3. Using electron flow in a diode the current flows from

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a) Anode to Cathode b)Cathode to Anode c) Cathode to Base 4. A control surface position feedback signal is a) proportional to surface position b)inversely proportional to surface position c) non-linear 5. In a PNP transistor, conventional current will flow when a) the emitter is more positive than the base b)the base is more positive than the emitter c) the collector is more positive than the emitter 6. An E&I transformer out of datum has a) equal and opposite voltages in each windings b)unequal and opposite voltages in both windings c) no voltage in either winding 7. A gyro will provide a) rate feedback b)velocity feedback c) positional feedback 8. In a common collector circuit the output and input are a) out of phase by 90o b)in phase c) out of phase by 60o 9. In velocity feedback the signal is a) in phase b)out of phase c) equal to the error signal

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10. When a hole diffuses from the p region to the n region a) it becomes a minority carrier in the n region b)lowers the potential barrier c) raises the potential barrier Answer 1. 2 3 4 5 6 7 8 9 10 A C B A A B C B B C This is exam number 22 1. A junction diode a) has one p-n junction b)is similar to a vacuum diode but cannot rectify c) can handle only small currents 2. A germanium diode is used for a) voltage stabilisation b)rectification c) signal detection 3. A germanium diode a) has a lower forward bias voltage than a silicon diode b)has a higher forward bias voltage than a silicon diode c) has the same forward bias voltage as a silicon diode 4. a VLSIC has a) less than 1000 gates b)more than 1000 gates c) more than 10,000 gates 5. A momentary input at the reset input of a flip flop will

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a) reset the true output to 0 b)reset the true output to 1 c) clock in new data from the data inputs 6. Which type of flip flop has only 1 data input a) RS b)JK c) D 7. A low pass filter has a) a capacitor in series and an inductor in parallel b)a capacitor in parallel and an inductor in series c) both capacitor and inductor in parallel 8. When you use an op amp as a buffer it has a) high input impedance and low output impedance b)low input impedance and high output impedance c) the same input an output impedance 9. What switches off a thyristor? a) Remove the gate voltage b)Remove supply voltage c) Reverse bias gate 10. When an SCR is switched on it has a) high resistance b)low resistance c) no change in resistance Answer 1. 2 3 4 5 6 7 8 9 10 A B A B A C B A B B

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This is exam number 23. 1. What is required for the switching of a monostable multivibrator a) one trigger pulse to switch on and another to switch off b)one trigger pulse to both switch on and off c) one trigger pulse to switch on and two trigger pulses to switch off 2. A transistor at saturation has a) high resistance b)low resistance c) zero resistance 3. A capacitor resistor coupled multistage amp lets a) AC and DC pass to the next stage b)AC pass only c) DC pass only 4. An oscillator operating at its natural frequency has feedback which is a) inphase b)90 degrees out of phase c) 180 degrees out of phase 5. What type of diode when forward biased holes and electrons recombine producing photons? a) gunn b)LED c) photodiode 6. What type of pulse is required to switch on a SCR a) positive b)negative c) positive and negative

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7. Which mathematical operation is performed by a modulator amplifier? a) Addition b)Subtraction c) Multiplication 8. What is meant by a bistable circuit? a) The circuit has 2 stable states and will stay in which one it is put b)The circuit has 2 stable states and will stay in both at the same time c) The circuit has 1 stable state and it can be negative or positive 9. A zener diode is designed to operate a) above its breakdown voltage b)below its breakdown voltage c) either above or below its breakdown voltage 10. A JFET is a) voltage sensitive b)current sensitive c) either of the above depending on resistance in the circuit Answer 1. 2 3 4 5 6 7 8 9 10 B B B A B A C A A A This is exam number 24. 1. A triac is a type of a) thyristor b)thermistor c) transistor

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2. A piece of pure Germanium a) has a deficit of electrons b)is electrically stable c) has an excess of electrons 3. If a junction diode is reverse biased too far, the output current would a) cease to flow b)increase c) reverse direction 4. An RC connected amp has a) no AC across b)no DC across c) even amounts of d.c and a.c across 5. When a PN junction is forward biased, it conducts via a) majority carrier b)minority carrier c) intrinsic carrier 6. Thermal runaway in a transistor refers to a) high current flow when temperature increases b)low current flow when temperature increases c) high current flow when temperature decreases 7. When is maximum voltage induced into the rotor of a control synchro transformer? a) 90 degrees (null position) b)0 degrees c) When spinning fast

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8. Resistors and capacitors are used to couple stages of amplifiers so that a) only d.c can be applied b)equal amounts of a.c and d.c can be applied c) only a.c can be applied 9. An astable multivibrator is a a) free running vibrator b)one which requires an input to switch on and off c) one which requires no input whatsoever 10. Op amps use what power supply? a) 26v a.c b)5v - 15v d.c c) 26v d.c Answer 1. 2 3 4 5 6 7 8 9 10 A B B B A A B C A B This is exam number 25. 1. To check the output of a synchro stator it would be preferable to use a) an Avometer b)a Valve Voltmeter c) a Cambridge Bridge 2. Synchro capacitors are connected into synchro systems to a) minimize the torque synchro stator current at null b)increase the accuracy of the control synchro c) act as spark suppression due to wear of the slip rings

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3. The purpose of the fly wheel incorporated in a synchro a) is to increase the driving force b)to prevent oscillations c) to prevent insect ingress 4. In a slab desynn transmitter the a) pick-offs form part of the circuit resistance b)pick-offs rotate on the slab resister c) pick-offs are connected to a spark suppressor 5. If, in a servo system, the amplitude from the feedback system is below normal, the servo will a) oscillate b)be sluggish in operation c) be overdamped 6. A desynn instrument has a positive irregular increasing error, you would adjust a) lever length b)lever angle c) lever angle and lever length 7. Torque synchro receiver bearing friction will cause a) hunting b)misalignment c) improved accuracy 8. A control synchro system pointer is a) actuated by a permanent magnet b)displaced by the torque of the stator c) motor driven 9. A D.C. signal converted to a phase sensitive A.C. is a) demodulation

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b)phase conversion c) modulation 10. If velocity feedback in a servo system is above optimum, this will cause a) sluggish operation b)hunting c) has no effect Answer 1. 2 3 4 5 6 7 8 9 10 B B B B A B B C C A This is exam number 26. 1. A device which has a high input impedance, low output impedance and high voltage gain is a a) Class A amp b)Class B amp c) Op-Amp 2. In an integrated circuit, the components are mounted by a) wires connecting them using conformal coating b)a three dimensional process with no connections between them required c) metal oxide film etched onto surface 3. For a NPN transistor to conduct the collector circuit has to be a) more positive than the emitter b)more positive than the base c) less positive than the emitter 4. The amount of rate feedback from a tachogenerator is a) proportional to speed

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b)inversely proportional to speed c) constant for all servo speeds 5. When forward biased, current flow is mainly due to the a) majority carriers b)minority carriers c) germanium bias junction 6. When forward biased the a) positive lead is connected to the N type and negative to the P type b)positive lead is connected to the P type and negative to the N type c) positive lead is connected to both N and P type 7. In a PNP transistor, which way does conventional current flow? a) Base to emitter b)Collector to emitter c) Emitter to Collector 8. In the Zener Diode suppressor shown, point X in respect to point Y should

be a) more negative b)more Positive c) either positive or negative 9. In an integrated circuit, the components are inserted a) manually b)automatically c) by doping in successive layers

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10. The typical voltage drop across an L.E.D is a) 2V b)4V c) 6V Answer 1. 2 3 4 5 6 7 8 9 10 C C B A A B C A C A This is exam number 27. 1. In an electronic circuit with an operational amplifier connected in the push-pull configuration, the circuit a) decreases impedance b)utilizes both sides of the input signal c) blocks half of the input signal 2. Pin 3 on an op-amp has a + symbol. This designates a) positive offset null b)positive input DC pin c) non-inverting input 3. An advantage of a FET when compared to a bi-polar transistor is a) the input resistance is lower b)the switching time is quicker c) the input resistance is higher 4. The semiconductor substrate used in 'chips' is most commonly a) germanium b)silicon c) phiidide

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5. Point X compared to point

a) Z is more positive b)Y is more negative c) Z is more negative 6. The typical bandwidth for an audio frequency amplifier is shown by line

a) X b)Y c) Z 7. What control system is used on an input that gives a controlled predetermined output? a) Open Loop b)Closed Loop c) Control Servo

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8. Increasing velocity feedback from optimum will give a) sluggish performance b)faster performance c) no change on the output 9. A rate control servo system with a steady input voltage will give a) constant speed b)increasing speed c) decreasing speed 10. Where are decoupling capacitors used in digital circuits? a) Between pins 1 & 8 b)Close to the +ve pin c) Close to the –ve pin Answer 1. 2 3 4 5 6 7 8 9 10 B C C B A A B A A B This is exam number 28. 1. What are the majority carriers for a forward biased PN junction device? a) Electrons b)Holes c) Electrons and holes 2. The resistance measured using an AVO between the Collector and Emitter of a transistor is a) same both ways b)smaller Collector to Emitter c) higher Collector to Emitter

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3. Germanium in its pure state is a) neutral b)positively charged c) negatively charged 4. Common Collector has the following characteristics a) Medium Voltage Gain, High Current Gain, Non-Inverted Output b)Low Voltage Gain, High Current Gain, Inverted Output c) Medium Voltage Gain, Low Current Gain, Inverted Output 5. Two push-pull transistors have what commoned? a) Bases b)Collectors c) Emitters 6. In a Common Emitter Amplifier RE is used for a) biasing b)stabilisation c) load control 7. If the reverse bias voltage across a diode is too high a) load current increases rapidly b)load current reverses c) load current reduces to zero 8. The rotor coil of a synchrotel a) is stationary b)rotates c) rotates only when a current flows in it 9. An increase in amplitude of a rate feedback signal will cause a) sluggish servo operation b)reduced hunting c) instable operation

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10. An increase in negative feedback a) increases system sensitivity b)decreases system sensitivity c) will make the driven device continuously rotate Answer 1. 2 3 4 5 6 7 8 9 10 C A A A C B A A B B This is exam number 29. 1. An integrated circuit is manufactured by a) computer hardware, which use individual circuits on ribbon b)doping impurities into layers of intrinsic material c) etching copper tracks onto an insulating board 2. A de-coupling capacitor in a PCB is used to a) minimise transient currents b)pass a.c only c) pass d.c only 3. A monostable vibrator a) is switched on by a trigger pulse then within a pre-set time will eventually return to its original state b)uses a trigger pulse to turn on and the same pulse to turn off c) uses one pulse to turn on and another to turn off 4. Position feedback is used to a) ensure control surface moves to the demanded position by the controls b)to prevent control surface oscillations while the surface is being moved

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c) indicate to the pilot the position of the load 5. The output from a control transformer is a) torque b)AC voltage c) DC voltage 6. The stator output voltages from a synchro resolver are a) DC b)AC single phase c) 3 phase 7. The purpose of synchro capacitors in a differential synchro transmission system a) to reduce stator current b)reduce rotor current c) reduce stator circuit impedance 8. A typical use for resolver synchros is a) in compass comparitor units b)engine power instrumentation c) fly by wire system 9. The purpose of a flywheel in a synchro receiver indicator is to a) prevent spinning or oscillation b)encourage spinning c) increase driving torque 10. A linear variometer is a) a special synchro giving ac output proportional to shaft angle b)a special auto transformer for synchro system power supplies c) an alternative term for a desynn system Answer

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1. 2 3 4 5 6 7 8 9 10 B B A A B B A A A A This is exam number 30. 1. In a synchrotel the rotating winding is a) the stator b)rotor c) neither 2. The receiver rotor in a torque synchro system oscillates over an arc of approx 75 degrees. The probable cause is a) short circuit between two stator lines b)two stator lines reversed c) one stator line open circuit 3. Synchro capacitors are fitted a) to provide critical damping b)to make additional damping features unnecessary c) to improve sensitivity and accuracy 4. The output of a control transformer is made a) phase and amplitude sensitive by direction and magnitude of the transmitter rotor movement respectively b)phase and amplitude sensitive by magnitude and direction of the transmitter rotor movement respectively c) phase sensitive by transmitter rotor excitation and amplitude sensitive by direction of transmitter rotor movement

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5. A transistor is used in a) current amplifier b)voltage amplifier c) both 6. An LED which emits green light uses a) gallium arsenide phosphide b)gallium phosphide c) gallium arsenide 7. An LED which emits red light uses a) gallium arsenide phosphide b)gallium phosphide c) gallium arsenide 8. A photodiode is operated under a) reverse bias conditions b)forward bias conditions c) reverse or forward bias conditions 9. To increase capacitance of a varactor diode a) reverse bias voltage is increased b)forward bias voltage is decreased c) reverse bias voltage is decreased 10. Which diode has a lower forward bias voltage? a) silicon b)germanium c) both the same Answer 1. 2 3 4 5 6 7 8 9 10 C A C A C B A A C B

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This is exam number 31. 1. A Zener diode is used for a) rectification b)voltage stabilisation c) voltage regulation 2. In the above diagram the phase of the input to the output is

a) in phase b)180 degrees out of phase c) 90 degrees out of phase 3. The above diagram shows a

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a) voltage doubler b)half wave rectifier c) full wave rectifier 4. A thyristor SCR is a a) unidirectional device b)bi-directional device c) multidirectional device 5. A bi-directional TRIAC has two SCRs connected in a) series parallel b)parallel series c) inverse parallel 6. A thyristor can be forward biased by a) positive pulse b)negative pulse c) positive or negative pulse 7. 'N' type materials are doped with a) acceptors b)donors c) acceptors and donors 8. A junction diode if reverse biased too far, the output will a) increase b)stop c) reverse

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9. The input of this circuit will be a) integrated b)differentiated c) logarithmic 10. The most suitable class of amplifier for a radio transmitter is a) A b)B c) C Answer 1. 2 3 4 5 6 7 8 9 10 C B A A C A B A A A This is exam number 32. 1. Under normal operating conditions X will be

a) negative with respect to Z b)positive with respect to Z c) negative with respect to Y 2. What is the base material of a PCB? a) Insulator b)Conductor

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c) Semiconductor 3. What does the output voltage of an op-amp depend upon? a) The resistors in the circuit b)The op amp bandwidth c) The gain of the op-amp 4. In which direction does the current flow on a PNP transistor when forward biased? a) Emitter to collector b)Collector to emitter c) Emitter to base 5. What does a resolver do? a) Resolves a position into sine and cosine components b)Adds two signals c) Resolves a movement into sine and cosine components 6. What component is used to turn AC to DC? a) Diode b)Transistor c) Thyristor 7. What is an intrinsic material? a) One with removed elements b)One with added elements c) A pure material 8. What does the colour of an LED depend upon? a) Material b)Voltage c) Current

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9. In an electronic circuit, if the anode of a diode is clamped to ground what is this called? a) A high level clamp b)A low level clamping circuit c) A negative limiting circuit 10. If the feedback is ideal damped, the signal will a) overshoots once and return back b)oscillate c) not overshoot Answer 1. 2 3 4 5 6 7 8 9 10 B A A A A A C A A A This is exam number 33. 1. The voltage drop of silicon diode is a) 0.3 V b)0.7 V c) 1 V 2. The negative feedback for integrator is connected across a a) resistor b)capacitor c) inductor 3. To decrease the capacitance of a varactor a) forward bias should be increased b)reverse bias should be decreased c) reverse bias should be increased

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4. In a printed board circuit, the surface resistance testing is a) the resistance between the tow inductors b)insulation resistance between adjacent printed conductor c) between the board and the conductor. 5. A Zener diode is used across the output for a power supply circuit to a) give a full wave rectification b)provide a steady DC voltage output without falling c) prevent thermal runway 6. If a diode has gone open circuit in a full wave bridge rectifier, the output frequency ripple is a) the same input frequency b)twice the input frequency c) half the input frequency 7. In a tachogenerator the output voltage is a) inversely proportional to the speed b)directly proportional to the speed c) zero Answer 1. 2 3 4 5 6 7 8 9 10 B B C B B C B 8. a) b) c) 9. a) b) c)

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10. a) b) c) c