الدورة الشتوية لعام 0 00.. 3. 4. 5. A silicon diode measures a high value of resistance with the meter leads in both positions. The trouble, if any, the diode is: open internally shorted shorted to ground A reverse-biased diode has the connected to the positive side of the source, and the connected towards the negative side of the source. cathode, anode base, anode ok cathode, base anode, cathode In an NPN transistor, the majority carriers in the base are: free electrons neither The ripple frequency of a bridge rectifier is: the same as the input frequency double the input frequency four times the input frequency cannot be determined holes both With a pure AC signal input to the circuit shown in Figure below, what output wave form would you expect to see on an oscilloscope display? 6. 3 The average value of the half-wave rectified output voltage is approximately of Vp. 3.8% 70.7% 4 63.6% 00% Examinations& evaluation unit winter.0
7. 8. الدورة الشتوية لعام 0 When the source voltage increases in a Zener regulator, which of these currents remains approximately constant? Series current Load current Refer to Figure below. The symbol is for: Zener current Total current 9. 0. a triac a UJT a diac an SCR The capacitance of a varactor diode: remains constant as the bias voltage varies decreases as the reverse bias voltage increases increases as the reverse bias voltage increases is usually 000 µf or more The output voltage for the circuit below is:.. 5V V 7V Zero volts In a transistor, the relation of the three transistor currents is: Ic = IE +Pc Ic = IB - IE IE = Ic + IB IC = IE + IB Refer to the figure below. The value of Ic at cut off is: 0.56 ma. ma 0.68 ma equal zero Examinations& evaluation unit winter.0
. 4. 5. الدورة الشتوية لعام 0 In a transistor, collector current is controlled by: collector voltage base current collector resistance all of the above Saturation and cutoff are operating conditions that are very useful when operating the transistor: as a linear amplifier as a current amplifier as a switch none of the above The information in the chart below indicates that the transistor is a/an: 6. 7. NPN type and that lead is the base lead. PNP type and lead is the base lead. NPN type and lead is the base lead. PNP type and lead is the base lead. A thyristor can be used as: a resistor a switch Refer to Figure below. This symbol identifies: an amplifier a power source a P-channel E MOSFET an N-channel D MOSFET a P-channel D MOSFET an N-channel E MOSFET Examinations& evaluation unit winter.0 3
8. الدورة الشتوية لعام 0 Refer to Figure below. If ID = 4 ma, the value of VDS IS: 9. V 8 V 4 V 0 V Refer to Figure below. The value of the voltage drop across RD is: 0. 0 V V 6 V 3 V The gate-source junction of a JFET is: normally not biased normally forward biased normally reverse biased a low resistance path for dc current when reverse biased.. 3. The SWR on a transmission line is infinity, the line is terminated in: a complex impedance a short circuit a pure reactance a pure Resistance The velocity factor of a transmission line is higher for a solid dielectric than for air increases the velocity along the transmission line depends on the dielectric constant of the material used is zero if Zo=ZL High- frequency waves are: reflected by the D layer, night time absorbed by the f layer non affected by the solar cycle reflected by the F layer, night time Examinations& evaluation unit winter.0 4
الدورة الشتوية لعام 0 4. 5. 6. 7. 8. 9. 30. 3. 3. Diffraction of electromagnetic waves may occur around the edge of a sharp obstacle is caused by reflections from the ground arises only with spherical wave fronts is caused by refraction from the ionosphere The antenna radiation of energy is more efficient when the time intervals between +Ve and Ve half cycles is short the time intervals between +Ve and Ve half cycles is long the mi point impedance is more capacitive the mi point impedance is more inductive The coaxial transmission lines are termed unbalanced since: they increase the power losses they match the load to the source they have one grounded conductor they have two grounded conductors When the two components of electric field are equal in magnitude, the electromagnetic wave polarization is elliptical circular The skip distance is: spherical horizontal the distance within which the wave can be received the minimum available distance required to make communication the maximum required distance to make communication the distance between the transmitter and the receiver Which of the following terms does not apply to the Yagi-array: parabolic antenna Bi- directional radiation Horn feed is used with a parabolic reflector to increase the gain of the system increase the beam width of the system reduce the size of the reflector reduce the size of the director folded dipole balance load To build λ/ dipole to receive a 00MHz broadcast, the actual optimum physical length of the antenna must be.43 meter 5 meter.57 meter 5.7 meter If a frequency of a signal is 3 0 4 Hz, then its wave length is: micro-meter milli-meter meter/second meter Examinations& evaluation unit winter.0 5
33. 34. الدورة الشتوية لعام 0 Characteristic impedance Z o for a transmission line is given by: Z o = Z o = L ohms C C ohms L The quarter-wave antenna generally: Z o = Z o = LC LC ohms ohms has one 4 pole with earth ground instead of the missing quarter wave has one pole with earth ground instead of the missing quarter wave 35. 36. 37. 38. 39. 40. has one pole with earth ground instead of the missing quarter wave has pole with earth ground instead of the missing quarter wave Higher frequency waves have: shorter wave length longer wave length medium wave length variable wave length Radio waves is propagated by sky wave: from the ionosphere from the troposphere in or close to earth in far to earth The troposphere thick is about: 0 miles 0 miles 30 miles 40 miles The angle between electric and magnetic fields in a wave guide is: 90 o 0 o 80 o 360 o Impedance inversion may be obtained with: a half wave line a quarter- wave line short- circuited stub an open- circuited stub Frequencies in the UHF range propagate by means of: space waves (LOS) sky waves surface waves (HOS) ground waves 4. 4. The square wave consist of: Odd harmonics Even harmonics Fundamental frequency Odd harmonics +even harmonics In the integrated LR circuit the output will be taken across the: Capacitor Resistor Diode Inductor Examinations& evaluation unit winter.0 6
43. 44. 45. 46. 47. 48. 49. 50. 5. 5. 53. الدورة الشتوية لعام 0 If the input trigger frequency of a Monostable multivibrator is 0MHz then the output pulse frequency is: 0KHz 0MHz 0MHz 0KHz The circuit that provides the sawtooth signal is called: Time base generator RC differentiator Slope generator All of the above Which of the following waveforms could be the output of the astable multivibrator? Sine wave Rectangular wave Sawtooth wave Trapezoidal wave In the differentiated CR circuit the output will be taken across the: Capacitor Diode Resistor Inductor In a bistable multivibrators, what minimum number of triggers is required to produce one gate? Four Two Three One In a transistor sawtooth generator, linearity is affected by: Input signal amplitude Gate length Fly back time The transistor in the multi-vibrator circuits acts as an: Amplifier Switch Sawtooth waveforms are used in: TV sets, computers, and telephones Radar sets, oscilloscopes, and computers TV sets, computers, and radios All of the above Filter Radar sets, oscilloscopes, and function generators Voltage source If the input trigger frequency of a Monostable multivibrator is 0MHz then the output pulse frequency is: 0KHz 0MHz 0KHz 0MHz The rate of voltage change across a capacitor is almost linear during: 0% of the charge curve 5% of the charge curve 37.7% of the discharge curve 63.3% of the charge curve For a square wave of a period of 00ms, the acceptable transition time is: 5s 5ms 50ms 0.5s Examinations& evaluation unit winter.0 7
الدورة الشتوية لعام 0 54. The output frequency of a Bistable multivibrator is: Double the input frequency One half of the input frequency Equals the input frequency None of the above 55. Which of the following pulses is used to change states in a flip flop? A trigger pulse A clipping pulse A modulating pulse An interference pulse Blocking oscillator **** In answering questions 56 through 60, refer to figure 56. The blocking oscillator is a special type of wave generator used to produce: square wave Sawtooth wave 57. 58. 59. Narrow pulse Non of the above If the frequency of the external trigger is 4kHz, & the free running frequency is 3kHz, then the out put frequency will be: khz 3kHz 4kHz 7kHz The parameters that determine the long of cut off region are: L,Rc C,R. L,C. L,R. The component that used to over come the over shoot is: L Opposite polarity of L & L Variable R R 60. The parameters that determine the pulse width are: L,R L,L L,R L,Rc Examinations& evaluation unit winter.0 8
الدورة الشتوية لعام 0 6. 6. 63. 64. 65. 66. 67. 68. 69. 70. 7. The instruction STA 5060h requires: byte 3 Bytes The flag register in 8085 microprocessor has: 4 flags 6 flags Accumulator is a part of: CU Memory bytes 4 bytes 5 flags 8 flags ALU Timing unit A register in the microprocessor that keeps track of the answer or results of any arithmetic or logic operation is the: stack pointer instruction pointer program counter accumulator A register in the microprocessor which is involved with pop and push operations is: SP AC The register which keeps the address of next instruction to be executed is: PC BP Clock is measured in: Bits per second Bytes A machine cycle refers to: fetching an instruction clock speed IP PC SP fetching, decoding and executing an instruction executing an instruction A baud Hertz One of the addressing modes not used in M6800 microprocessor is: Direct Register Direct The address length in 8080 microprocessor is: 8 The number of data lines in 8080 microprocessor is: 3 6 Immediate Register In-Direct 4 6 0 8 Examinations& evaluation unit winter.0 9
7. 73. X الدورة الشتوية لعام 0 The circuits in the 8085A that provide the arithmetic and logic functions are called the: CPU ELU ALU How many buses are connected as part of the 8080 microprocessor? 8 3 Suppose we have the following memory: CU 5 LOAD 00 ADD 00 memory address contents 00 05 0 0 0 0 74. 75. 76. 77. 00 0 0 00 0 0 What will be in the accumulator after executing instruction and 300 05 Using question X what will be in the accumulator after executing instruction and 0 05 LOAD @00 ADD @0 Using question X what will be in the accumulator after executing instruction, and 3 0 00 The 8080 is: 3 6-bit parallel CPU 8-bit parallel CPU LOAD #00 ADD #00 STORE 00 50 0 0 06 05 300 8-bit serial CPU 6-bit serial CPU Examinations& evaluation unit winter.0 0
78. 79. 80. الدورة الشتوية لعام 0 Which of the following are the three basic sections of a microprocessor unit? operand, register, and arithmetic/logic unit (ALU) control and timing, register, and arithmetic/logic unit (ALU) control and timing, register, and memory arithmetic/logic unit (ALU), memory, and input/output The number of pins that the 8085 microprocessor has is: 60 8 40 48 Which signal controls the lines AD0-AD7 ALE RD WR IOM 8. 8. 83. 84. 85. 86. 87. Sinosoidal wave signal with 3GHz frequency find its wave length if you know that the speed of light= 3*0 8 m/s : 0. ms 90 m The period of a khz sine wave signal is: ms μs 0 cm 9MHz 0 ms 0 μs The circuit function that recovers the information signal from the carrier in a receiver is the: detector circuit IF section mixer oscillator The modulation index m of an amplitude modulated signal is given by : Vm/Vc Vc + Vm Vc/Vm VVm The problem of increasing in amplitude that interduced by noise can be fixed by using of: limmiter amplifier modulater frequency filter Changing the electrical energy of the information signal into sound energy is called: detection selection reproduction amplification A 350 V carrier is being amplitude modulated by 30 V audio frequency signal, the modulation index is : zero 54 5 66 Examinations& evaluation unit winter.0
88. 89. 90. الدورة الشتوية لعام 0 What are the principal frequencies that appear at the output of a mixer circuit? Two and four times the original frequency The sum, difference and square root of the input frequencies The original frequencies and the sum and difference frequencies.44 and 0.707 times the input frequency A circuit that converts frequency or phase change into a DC voltage is called a/an: AM converter Phase detector Calculate the modulation depth: DC phasor PLL 9. 9. 93. 94. 95. 0.6.67 Examinations& evaluation unit winter.0 0.5 The power dissipated by an amplitude modulated wave is 00 W when the depth of modulation is 40%.the modulation depth needed to increase the power to 0W is: 64% 60% 5 77% 67% The bandwidth of an FM system,when mf = 5 and Δf = 75 khz is equal to: 40 khz 80 khz 0 khz 90 khz The telephone signal has a frequency between 300 3400 Hz. The sampling frequency that represents this signal is: 600 Hz 6800 Hz One of the advantages of ASK over FSK is: it needs less bandwidth it has two carrier signals 300 Hz 600 Hz it needs twice bandwidth it hasn t a carrier In comparison between PSK and 4PSK with respect to the bandwidth needed: PSK needs less bandwidth 4PSK needs half the bandwidth 4PSK needs double bandwidth both need same bandwidth
96. 97. الدورة الشتوية لعام 0 The type of AM used for sound broadcasting is: DSB-SC JJB DSB VSB The over gain of the system shown below is: 98. 99. 00. 3 db 6db -6db 3db Am circuit used signal generator for? Broadcast transmitter Testing and alignment Generate square pulse None of the above The length of the dipole in bi-directional antenna is: 0.5λ 0.5λ λ.5λ The band frequency used in sky wave: LF VLF HF MF Examinations& evaluation unit winter.0