1. What gives the colour of an LED?. (Level 2), A. The active element., B. The plastic it is encased in., C. The type of gas used inside it., 2. A junction diode. (Level 2), A. is similar to a vacuum diode but cannot rectify., B. has one p-n junction., C. can handle only very small currents., 3. A servo system may include a brake, an automatic trim system is one example where a brake is used. The brake is. (Level 1), A. applied when trimming is complete to prevent stabilizer creep., B. applied during trimming to prevent oscillations about the demand position., C. applied during trimming to prevent servo runaway., 4. In a control synchro the stator current ceases to flow when. (Level 1), A. the CT rotor is at null., B. when power is removed., C. when the two rotors are aligned., 5. Reverse bias. (Level 2), A. raises the potential barrier., B. lowers the potential barrier., C. greatly increases the majority carrier current., 6. A diode connected across a relay coil is used to. (Level 2), A. dissipate coil spikes on switch off., B. allow the coil to energize with only one polarity., C. cause a delay in switching on., 7. To check the forward resistance of a diode with a multimeter, the lead connected to the positive terminal is put to the. (Level 2), A. anode., B. cathode., C. either anode or cathode., 8. A thyristor has which of the following?. (Level 2), A. A positive temperature coefficient., B. High resistance when switched off., C. High resistance when switched on., 9. In an LED, what is used to make the colour?. (Level 2), A. The plastic lens cover., B. The electrons., C. The doping material., 10. An atom with 5 electrons in its outer shell is part of. (Level 2), A. a C type material., B. a P type material., C. an N type material., 11. A thyristor is commonly used for. (Level 2), A. overvolts regulation., B. voltage regulation., C. rectification., 12. A diode which emits photons when conducting is a. (Level 2), A. light emitting., B. varactor., C. zener., 13. The electrodes of an SCR are. (Level 2), A. gate, cathode, anode., B. source, drain, gate., C. anode, cathode, source., 14. A germanium diode is used for. (Level 2), A. rectification., B. voltage stabilization., C. modulation., 15. What gives an LED its colour?. (Level 2), A. A gas., B. The cover., C. Composition and impurity of the compound., 16. Forward voltage of a silicon diode is. (Level 2), A. 1.6V., B. 0.6V., C. 0.2V., 17. What is the typical volts drop across an LED. (Level 2), A. 0.2V., B. 0.4V., C. 1.6V., 18. What diode gives off light photons when forward biased. (Level 2), A. LED., B. Gunn diode., C. Schottky diode., 19. 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. (Level 2), A. forward biased not conducting., B. reverse biased not conducting., C. forward biased conducting., 20. Using electron flow in a diode the current flows from. (Level 2), A. Anode to Cathode., B. Cathode to Base., C. Cathode to Anode., 21. Tunnel diodes have the following characteristics. (Level 2), A. Heavily doped P-N junction with an extremely narrow depletion region., B. Lightly doped P and N regions and a high reverse breakdown voltage., C. Lightly doped P region, heavily doped N region and has a fast response time., 22. The capacitance of a varactor diode is. (Level 2), A. inversely proportional with reverse bias voltage., B. a linear function of applied reverse bias voltage., C. directly related to the forward bias voltage., 23. A semiconductor doped with an element having a valency of 5 will produce. (Level 2), A. an N type material., B. either an N type or a P type depending on what type of semiconductor material is used., C. a P type material., 24. In a diode clamper, if the resistor is removed making the time constant equal to C x r where r is the reverse resistance of the diode, this will ensure a. (Level 2), A. long time constant., B. short time constant., C. Very Long Time Constant., 25. Why is a diode put in parallel with an LED?. (Level 2), 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., 26. PIN diodes are used mainly for. (Level 2), A. linear rectifiers., B. fast switching devices., C. voltage operated rectifiers., 27. To enable an IMPATT diode to operate correctly, it must be. (Level 2), A. connected to a resonant circuit., B. used in its reverse bias mode., C. operated in its negative resistance range., 28. What type of diode would be used to stop voltage spikes across a coil of a relay?. (Level 2), A. Gunn diode., B. Double acting diode., C. Schottky diode., 29. What is a schottky diode used for?. (Level 2), A. Rectification., B. Stabilization., C. Very high frequency applications., 30. When a hole diffuses from a p-region to the n-region it. (Level 2), A. becomes a minority carrier in the n-region., B. lowers the potential barrier., C. raises the potential barrier., 31. The junction barrier offers opposition to only. (Level 2), A. holes in the p-region., B. free electrons in the n-region., C. majority carriers in both regions., 32. Avalanche breakdown occurs when. (Level 2), A. reverse bias exceeds a certain value., B. forward bias exceeds a certain value., C. forward current becomes excessive., 33. 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. (Level 2), A. when the flow of minority carriers is sufficient to cause an avalanche breakdown., B. when the depletion layer becomes larger than the space charge area., C. only after the forward bias exceeds the potential barrier., 34. A band pass filter excludes frequencies. (Level 2), A. below the frequency required only., B. above and below the frequency required., C. above the frequency required only., 35. In an unbiased p-n junction, current flow is. (Level 2), A. zero, because equal but opposite currents are crossing the junction., B. zero, because no charges are crossing the junction., C. due to the diffusion of minority carriers only., 36. When testing the forward bias of a diode with a multimeter. (Level 2), A. the positive lead of the ohmmeter is placed on the anode., B. it does not matter which terminal the positive lead of the ohmeter is placed., C. the positive lead of the ohmmeter is placed on the cathode., 37. What diode is used to stop power spikes in a coil?. (Level 2), A. Gunn diode., B. Schottky diode., C. Two directional zener diode., 38. What type of diode when forward biased holes and electrons recombine producing photons?. (Level 2), A. LED., B. Photodiode., C. Gunn., 39. A zener diode is designed to operate. (Level 2), A. below its breakdown voltage., B. either above or below its breakdown voltage., C. above its breakdown voltage., 40. A triac is a type of. (Level 2), A. thermistor., B. transistor., C. thyristor., 41. If a junction diode is reverse biased too far, the output current would. (Level 2), A. reverse direction., B. cease to flow., C. increase., 42. When a PN junction is forward biased, it conducts via. (Level 2), A. intrinsic carrier., B. majority carrier., C. minority carrier., 43. If the reverse bias voltage across a diode is too high. (Level 2), A. load current reduces to zero., B. load current increases rapidly., C. load current reverses., 44. An LED which emits green light uses. (Level 2), A. gallium phosphide., B. gallium arsenide., C. gallium arsenide phosphide., 45. An LED which emits red light uses. (Level 2), A. gallium phosphide., B. gallium arsenide phosphide., C. gallium arsenide., 46. A photodiode is operated under. (Level 2), A. reverse bias conditions., B. forward bias conditions., C. reverse or forward bias conditions., 47. Which of the following describes the characteristics of a Thyristor?. (Level 2), A. High voltage handling., B. High power handling., C. High current handling., 48. To increase capacitance of a varactor diode. (Level 2), A. reverse bias voltage is increased., B. reverse bias voltage is decreased., C. forward bias voltage is decreased., 49. A bi-directional TRIAC has two SCRs connected in. (Level 2), A. series parallel., B. inverse parallel., C. parallel series., 50. A thyristor can be forward biased by a. (Level 2), A. positive or negative pulse., B. negative pulse., C. positive pulse., 51. N' type materials are doped with. (Level 2), A. acceptors., B. acceptors and donors., C. donors., 52. In an electronic circuit, if the anode of a diode is clamped to ground. What is this called?. (Level 2), A. A negative clamping circuit., B. A negative limiting circuit., C. A positive clamping circuit., 53. In an NPN transistor the P is the. (Level 1), A. collector., B. emitter., C. base., 54. When compared to a photo diode, a photo transistor. (Level 1), A. is less sensitive to light levels., B. responds faster to changes of light., C. is slower to respond to changes of light., 55. For correct operation of a transistor, the following conditions must apply. (Level 1), A. The base-emitter junction must be forward biased and the base-collector junction must be greater than 0.7 volts., B. For an NPN transistor the base-emitter junction must be forward biased and for a PNP transistor the base emitter junction must be reverse biased., C. The base-collector junction must be reverse biased and the base-emitter junction must be forward biased., 56. Current gain in a common emitter amplifier is given the symbol. (Level 1), A. Β., B. a., C. Hcg., 57. When a positive voltage is applied to the base of a normally biased n-p-n common emitter amplifier. (Level 1), A. the collector voltage goes less positive., B. the emitter current decreases., C. the base current decreases., 58. Light Emitting Diodes (LEDs). (Level 2), A. emit light of only one wavelength dependent on type., B. have very wide viewing angles., C. are easily damaged if forward biased b more than 5V., 59. Which way does conventional current flow in a PNP junction?. (Level 1), A. Emitter to base., B. Collector to base., C. Collector to emitter., 60. For conduction of a transistor, the emitter junction is. (Level 1), A. forward or reverse as appropriate to the input signal., B. reverse biased., C. forward biased., 61. If light entering a photo transistor decreases, the current to the collector. (Level 1), A. decreases., B. remains the same., C. increases., 62. A silicon bi-polar transistor with two depletion zones. (Level 1), A. operates by varying electric fields., B. is a voltage operated device., C. consists of 3 slices of semiconductor material., 63. "To decrease the voltage gain of a common emitter amplifier you would increase the resistance in the." (Level 1), A. base circuit., B. emitter circuit., C. collector circuit., 64. The current I/P and O/P waveforms in a common emitter amplifier are. (Level 1), A. out of phase., B. in phase., C. 90° out of phase., 65. Which mode of operation provides the best high frequency response? Common. (Level 1), A. emitter., B. base., C. collector., 66. A FET when compared to a junction transistor is. (Level 1), A. low impedance., B. current operated., C. high impedance., 67. One characteristic of the emitter follower is. (Level 1), A. low resistance output., B. low current amplification., C. high voltage amplification., 68. What are the ideal characteristics of an Op Amp?. (Level 1), A. Infinite gain, infinite input Impedance and infinite output impedance., B. Infinite gain, infinite input Impedance and zero output impedance., C. Low gain, infinite input Impedance and zero output impedance., 69. In a semiconductor junction diode, electrons are the minority carriers. (Level 2), A. within the P region., B. within the N region., C. in both the N and P regions., 70. What gate does the following Boolean expression represent F = A.B.C. (Level 1), A. AND., B. OR., C. NOT., 71. What gate does the following Boolean expression represent F = A+B+C. (Level 1), A. NOR., B. OR., C. NOT., 72. In an integrated circuit, the components are mounted. (Level 1), A. by metal screws., B. by metal oxide film., C. by means of wires connecting them., 73. A non-inverting op-amp. (Level 1), A. has an inverting input and a non-inverting output., B. a non-inverting input connection only., C. has a non-inverting input and an inverting output., 74. In an operational amplifier, the two input waves are the same amplitude, same frequency, but exactly anti-phase. What would the output be?. (Level 1), A. Double., B. Zero., C. Half., 75. In the following Boolean algebra statement, which gate is described?. F = A + B + C. (Level 1), A. And., B. Or., C. Not., 76. The voltage supply to a Complimentary Metal Oxide Semiconductor (CMOS) integrated circuit must be. (Level 1), A. 0 V is 5 V DC., B. 3V to 18V DC., C. 3V to 15V AC., 77. How are the pins numbered on an op-amp IC?. (Level 1), A. from left to right from the dot., B. counter clockwise from the dot., C. clockwise from the dot., 78. On an integrated circuit the hole in the top left corner is pin 1. The pins are counted. (Level 1), A. clockwise., B. from left to right., C. anticlockwise., 79. A single integrated circuit Op Amp has how many pins?. (Level 1), A. 7, B. 8, C. 4, 80. A silicon diode, when compared to a germanium diode has. (Level 2), A. a higher forward bias voltage., B. the same forward bias voltage., C. less forward bias voltage., 81. A logic circuit with more than one gate will have. (Level 1), A. 2 or more outputs., B. one of 2 states of logic output., C. an analogue output., 82. Components on an integrated circuit are. (Level 1), A. on the surface., B. in the solid., C. don't need them., 83. A VLS IC has. (Level 1), A. more than 10,000 gates., B. less than 1000 gates., C. more than 1000 gates., 84. When compared to a system that is constructed on one board, a modular system using Printed Circuit Boards (PCBs) is. (Level 1), A. harder to fault find., B. more expensive for spares., C. easier to fault find., 85. A Printed Circuit Board (PCS) is constructed of a plastic laminate which has bonded to one or both sides. (Level 1), A. a thin sheet of copper., B. various thicknesses of copper., C. a thick sheet of copper., 86. How is a PCB protected after manufacture?. (Level 1), A. By conformal coating., B. With non-conductive varnish., C. With wax., 87. A multi-layer PCB has. (Level 1), A. two or more layers on one or both sides., B. one layer on either side., C. two or more layers connected in series., 88. When removing a microprocessor. (Level 1), A. ensure the power is OFF to avoid static discharge., B. no damage is done by static discharge., C. considerable damage can be done by static discharge., 89. On a PCB, a decoupling capacitor is used to get rid of transient currents between which points?. (Level 1), A. The electronic circuit and the aircraft ground., B. The negative rail and the rest of the circuit., C. Interspaced along the circuit., 90. A decoupling capacitor in a PCB is used to. (Level 1), A. minimise transient currents., B. pass DC only., C. pass AC only., 91. A zener diode. (Level 2), A. allows current to flow in one direction., B. stabilizes voltage at a predetermined level., C. acts like a switch., 92. When a servomotor overshoots after a step input and oscillates it is. (Level 1), A. under damped., B. over damped., C. critically damped., 93. A reduction from the optimum setting of the velocity feedback in a servo loop could cause. (Level 1), A. instability., B. slow response., C. ow servo gain., 94. The phase difference between the supplies of a two phase induction motor is. (Level 1), A. 90°., B. 180°., C. 0°, 95. If the rotor of the receiver in a torque synchro system was prevented from aligning with the transmitter rotor, then. (Level 1), A. the transmitter rotor will turn to align with the receiver rotor., B. the receiver will hunt., C. the receiver will overheat., 96. An E&I bar output at datum has. (Level 1), A. an imbalance of voltages in the secondary windings., B. no induced voltage in the secondary windings., C. equal and opposite voltages induced in the secondary., 97. The result of cross connecting two of the transmission leads in a torque synchro system and then turning the rotor of the transmitter 60° clockwise would be. (Level 1), A. the receiver would move 60° clockwise., B. the receiver would move 60° anticlockwise., C. the receiver would move 120° anticlockwise., 98. The control windings of a two phase servomotor is supplied with AC voltage of. (Level 1), A. variable amplitude, variable phase., B. variable phase., C. constant amplitude., 99. If the rotor of a control synchro sticks. (Level 1), A. the system hunts., B. the position feedback will oscillate., C. high current will flow., 100. With the reversal of the connections to the rotor of the transmitter of a torque synchro, the position of the receiver rotor will be. (Level 1), A. changed by 120°., B. unchanged., C. changed by 180°.

Module 4 (p1)

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