Electronics Pre-Board PDF

TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY...

TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING Electronics D. 2 watts 1. Current flows in a circuit when 6. How many joules of energy will a 10 W A. a switch is opened lamp dissipate in one minute? B. a switch is closed * A. 10 joules C. the switch is either open or closed B. 60 joules D. there is no voltage C. 600 joules * 2. The maximum resistance value for a D. 3600 joules brown, red, yellow, gold resistor in ohms 7. When is a capacitor fully charged? is A. when the voltage across its plates A. 126,000 * is of the voltage from ground to B. 126,600 one of its plates C. 114,000 B. when the current through the D. 132,000 capacitor is the same as when the 3. How do fixed resistors usually fail? capacitor is discharged * A. slowly over time C. when the voltage across the plates B. by increasing their value is 0.707 of the input voltage C. by becoming an open circuit * D. when the current through the D. by increasing their value and capacitor is directly proportional becoming an open circuit to the area of the plates 4. With Ohm's law, if voltage increases and 8. What is the angle theta value for a 5.6 F resistance stays the same: capacitor and a 50-ohm resistor in series A. current remains the same with a 1.1 kHz, 5 Vac source? B. power decreases A. 27.3 degrees C. current increases * B. 62.7 degrees D. resistance decreases C. –27.3 degrees * 5. With 1 mA of current, what wattage D. –62.7 degrees rating should a 470-ohm resistor have? 9. Electricity may be generated by a wire: A. 1/4 watt * A. carrying current B. 1/2 watt B. wrapped as a coil C. 1 watt C. that has neutral domains  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING D. passing through a flux field * A. the magnetic field generated 10. The electrical energy consumed by a coil around a conductor when a is stored in the form of: current passes through it * A. an electrical field B. the magnetic field generated in a B. a force field conductor by an external voltage C. an electrostatic field C. the voltage caused by a magnetic D. a magnetic field * field in a conductor 11. What is magnetic flux? D. the current generated by an A. the number of lines of force in external magnetic field webers * 15. What are the properties that determine B. the number of lines of force in the inductance of a coil? maxwells A. Length of wire, number of turns, C. the number of lines of force in type of core material, length of teslas core D. the number of lines of force in flux B. Number of turns, type of wire, density length of core, and cross-sectional 12. As current travels within a conductor: area of core A. the magnetic field aids the current C. Type of core material, number of B. a magnetic field is developed turns, cross-sectional area of core, around it * and length of core * C. the wire tries to point north D. Type of core material, type of wire, D. an electrostatic field opposes the number of turns, and cross- current sectional area of core 13. What is hysteresis? 16. An inductor is in series with a voltage A. lead between voltage and current source, an open switch, and a resistor. B. lag between voltage and current The instant the switch is closed, the C. lead between cause and effect inductor acts like D. lag between cause and effect * A. a resistor 14. What is electromagnetism? B. a voltage source C. a short  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING D. an open * 17. If a charged capacitor is disconnected from a circuit, it will: A. immediately discharge B. recharge C. remain charged D. leak the charge * 18. The unit for reluctance is A. tesla in Fig1. B. At/Wb * Fig.1 C. At/m A. 4.16 V D. Wb B. 416 mV 19. What is the magnetomotive force in a 75- C. 4.16 V turn coil of wire when there are 4 A of D. 41.67 V * current through it? 22. Find the Thevenin equivalent voltage A. 18.75 At between terminals A and B of the circuit B. 30 At given below. Fig.1 C. 300 At * A. 120 ohms D. 187 At B. 288 ohms 20. A 12 V source has an internal resistance C. 100 ohms of 90. If a load resistance of 20 is D. 70 ohms * connected to the voltage source, the load 23. What is the peak-to-peak voltage of the power, PL, is waveform in Fig2? A. 23.8 W B. 2.38 mW C. 2.38 W D. 238 mW * 21. Find the Thevenin equivalent voltage Fig2 between terminals A and B of the circuit A. 2 V B. 4 V  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING C. 6 V C. 7 V D. 8 V * D. 12 V 24. What is the average voltage of the 28. In a parallel RLC circuit, which value may waveform in Fig2? always be used as a vector reference? A. 2 V A. current B. 4 V B. reactance C. 6 V * C. resistance D. 8 V D. voltage * 25. A half-cycle average voltage of 12 V is 29. What is the Q (Quality factor) of a series equal to what rms voltage? circuit that resonates at 6 kHz, has equal A. 13.33 V * reactance of 4 kilo-ohms each, and a B. 8.48 V resistor value of 50 ohms? C. 18.84 V A. 0.001 D. 7.64 V B. 50 26. What is the instantaneous peak voltage at C. 80 * 250° on a 6 V peak sine wave? D. 4.0 A. +5.64 V 30. What is the resonant frequency in Fig4? B. –5.64 V * C. +26.13 V D. –26.13 V 27. What is the peak voltage across R3 in Fig3? A. 11.6 Hz B. 275.8 Hz C. 1.5 kHz D. 3.2 kHz * 31. Series RLC voltage or impedance totals must be calculated by: Fig3 A. subtracting the values A. 1.2 V B. graphing the angles B. 5 V *  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING C. adding vectors * C. wavelength * D. multiplying the values D. period 32. When XC = XL the circuit: 37. The current in an AC circuit is flowing in A. draws maximum current what direction? B. applied voltage is zero A. clockwise C. is at resonance * B. counterclockwise D. draws minimum current C. in both directions at the same time 33. The peak value of a triangular wave is 3V. D. 50% of the time clockwise and 50% the peak-to-peak is __. of the time counterclockwise * A. 1.5 V 38. The movement of free electrons in a B. 3 V conductor is called C. 4.5 V A. voltage. D. 6 V * B. current. * 34. The impedance of an inductor is __. C. recombination. A. -jwL D. equilibrium. B. +jwL * 39. For a forward-biased diode, the barrier C. -1/(jwL) potential ________ as temperature D. +1/(jwL) increases. 35. At any resonant frequency, what voltage A. Decreases * is measured across the two series reactive B. remains constant components? C. increases A. applied D. zeroes out B. reactive 40. An n-type semiconductor material C. zero * A. is intrinsic. D. inductive and capacitive B. has trivalent impurity atoms 36. The distance that a signal's energy can added. travel in the time it takes for one cycle to C. has pentavalent impurity atoms occur is called the signal's: added. * A. amplitude D. requires no doping. B. frequency  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING 41. Single-element semiconductors are B. a Schottky diode. characterized by atoms with ____ valence C. a Gunn diode. electrons. D. a varactor. * A. 3 46. Which is the symbol for LED? B. 4 * C. 5 D. 2 42. Under normal conditions a diode conducts current when it is A. reverse-biased. A. (a) * B. forward-biased. * B. (b) C. avalanched. C. (c) D. saturated. D. (d) 43. The boundary between p-type material 47. The normal operating region for a zener and n-type material is called diode is the A. a diode. A. forward-bias region. B. a reverse-biased diode. B. reverse-bias region. C. a pn junction. * C. zero-crossing region. D. a forward-biased diode. D. reverse-breakdown region. * 44. An ideal diode presents a(n) ________ 48. An LED is forward-biased. The diode when reversed-biased and a(n) ________ should be on, but no light is showing. A when forward-biased. possible trouble might be A. short, open A. the diode is open. * B. open, open B. the series resistor is too small. C. short, short C. none. The diode should be off if D. open, short * forward-biased. 45. You have an application for a diode to be D. the power supply voltage is too used in a tuning circuit. A type of diode to high. use might be 49. The process of emitting photons from a A. an LED. semiconductive material is called  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING A. photoluminescence. C. 0.2 V. B. gallium arsenide. D. VCC. C. electroluminescence. * 54. A certain transistor has IC = 15 mA and IB D. gallium phosphide. = 167 A; DC Beta is: 50. A transistor amplifier has a voltage gain A. 15 of 100. If the input voltage is 75 mV, the B. 167 output voltage is: C. 0.011 A. 1.33 V D. 90 * B. 7.5 V * 55. What are the two types of bipolar C. 13.3 V junction transistors? D. 15 V A. npn and pnp * 51. For normal operation of a pnp BJT, the B. pnn and nnp base must be ________ with respect to the C. ppn and nnp emitter and ________ with respect to the D. pts and stp collector. 56. The value of DC Beta A. negative, negative A. is fixed for any particular B. positive, negative transistor C. positive, positive B. varies with temperature D. negative, positive * C. varies with IC 52. When a transistor is used as a switch, it is D. varies with temperature and IC * stable in which two distinct regions? 57. Which of the following is true for an npn A. saturation and active or pnp transistor? B. active and cutoff A. IE = IB + IC * C. saturation and cutoff * B. IB = IC+ IE D. none of the above C. IC = IB + IE 53. For a silicon transistor, when a base- D. none of the above emitter junction is forward-biased, it has 58. For a JFET, the value of VDS at which ID a nominal voltage drop of becomes essentially constant is the A. 0.7 V. * A. pinch-off voltage. * B. 0.3 V. B. cutoff voltage.  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING C. breakdown voltage. 63. Which of the following devices has the D. ohmic voltage. highest input resistance? 59. What is the order of doping, from heavily A. diode to lightly doped, for each region? B. JFET A. base, collector, emitter C. MOSFET * B. emitter, collector, base * D. bipolar junction transistor C. emitter, base, collector 64. Identify the n-channel D-MOSFET. D. collector, emitter, base 60. The ________ has a physical channel between the drain and source. A. D-MOSFET * B. E-MOSFET A. (a) * C. V-MOSFET B. (b) D. MASFIT C. (c) 61. What type(s) of gate-to-source voltage(s) D. (d) can a depletion MOSFET (D-MOSFET) 65. IGFET is also knows as __. operate with? A. BJT A. zero B. MOSGIR B. positive C. MOSFET * C. negative D. MISFIT D. any of the above * 66. Which of the following ratings appear(s) 62. On the drain characteristic curve of a in the specification sheet for an FET? JFET for VGS = 0, the pinch-off voltage is A. Voltages between specific A. below the ohmic area. terminals B. between the ohmic area and the B. Current levels constant current area. C. Power dissipation C. between the constant current area D. All of the above * and the breakdown region. * D. above the breakdown region.  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING 67. What is the level of drain current ID for impedance will __. gate-to-source voltages VGS less than (more negative than) the pinch-off level? A. zero amperes * B. IDSS C. Negative value D. Undefined 68. What is the level of IG in an FET? A. Zero amperes * Fig6 B. Equal to ID A. increase, increase C. Depends on VDS B. increase, decrease * D. Undefined C. decrease, decrease 69. Which of the following controls the level D. decrease, increase of ID? 72. Refer to Fig6. If R1 = 50kohms and A. VGS * R2=500kohms, what is the input B. VDS impedance? C. IG A. 500 kohms D. VDG B. 50 kohms * 70. In which of the following are operational C. 5 kohms amplifiers (op-amps) NOT used? D. 500 ohms A. Oscillators 73. What is the level of the voltage between B. Filters the input terminals of an op-amp? C. Instrumentation circuits A. Virtually zero * D. Clipper * B. 5 V 71. Refer to Fig6. If the value of R1 decreases, C. 18 V the voltage gain will __ and the input D. 22 V 74. In which of the following operations is the resulting output signal of the differential amplifier near zero? A. Single-ended  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING B. Double-ended 78. The circuit in Fig7 is __. C. Common-mode D. None of the above 75. An amplifier with a voltage input and current output. A. Voltage amplifier B. Current amplifier C. Transimpedance A. inverting amplifier D. Transconductance * B. noninverting amplifier 76. Most practical alternators generate C. differentiator electricity from D. integrator A. a coil rotating within a magnetic 79. What is the slew rate of an op-amp if the field output voltages change from 2 V to 3 V in B. a magnetic field rotating around 0.2 ms? fixed windings * A. 5 V/ms * C. a permanent magnet rotating B. 3 V/ms within a varying electromagnetic C. 2 V/ms field D. 1 V/ms D. none of the above 80. The maximum rate of change of the 77. What does the CRT oscilloscope display? output voltage in response to a step input A. voltage and period * voltage is the ________ of an op-amp. B. current and frequency A. time constant C. rms voltage and current B. maximum frequency D. frequency and voltage C. slew rate * D. static discharge  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING 81. This circuit in Fig8 is an example of a A. 1/9. B. 1/30. C. 1/3. D. 1/29. * 85. What is the minimum frequency at which a crystal will oscillate? A. seventh harmonic B. third harmonic ________. C. fundamental * Fig8 D. second harmonic A. single-ended input 86. The feedback signal in a(n) ________ B. double-ended (differential) input * oscillator is derived from a capacitive C. double-ended output voltage divider in the LC circuit. D. common-mode operation A. Hartley 82. Only the condition A = ________ must be B. Wien satisfied for self-sustained oscillations to C. Armstrong result. D. Colpitts * A. 0 87. Sinusoidal oscillators operate with B. –1 ________ feedback. C. 1 * A. Positive * D. None of the above B. Negative 83. The feedback signal in a(n) ________ C. Strong oscillator is derived from an inductive D. Weak voltage divider in the LC circuit. 88. The resonant frequency of an LC A. Hartley * oscillator depends on __. B. Armstrong A. R C. Colpitts B. L D. Wien C. Both R and L 84. The attenuation of the three-section RC D. Both L and C * feedback phase-shift oscillator is  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING 89. "Series" and "parallel" as applied to dc B. Converter motors refer to C. Inverter A. the connection of the motor and D. Transducer * controller 94. The part of the generator that cuts the B. the connection of the field coil and magnetic flux. armature windings * A. Armature * C. the connection of the brush and B. Knife commutator C. Blade D. the connection of the motor D. Right hand rule batteries 95. What are the effects of moving a closed 90. The component that produces power in wire loop through a magnetic field? an electromagnetic generator is called the A. A voltage is induced in the wire. A. Armature * B. A current is induced in the wire. B. field winding C. The polarity across the wire C. commutator depends on the direction of D. brush motion. 91. The capacity of a wet cell is given in __. D. All of the above * A. Ampere-hours * 96. The part of the PMMC that moves when B. Coulomb-sec the measured current passed through it. C. Ampere per sec A. Deflection pointer D. Coulomb per sec B. Moving coil * 92. Which electromagnetic device uses C. Magnetic poles brushes and a commutator? D. Field poles A. A speaker 97. A PMMC ohmmeter circuit is essentially a B. A dc generator * voltmeter circuit with __. C. A relay A. Unknown resistance D. A solenoid B. Zero-ohm adjust 93. A device that converts one form of energy C. calibration to another. D. Battery * A. Sensor  TOP ECE REVIEW CENTER Unit 1, 4th Floor, España Place Bldg., 1139 Adelina St. corner España, Sampaloc, Manila TEL NO. 0915 274 3061 / 0920 460 7097 JOSE RIZAL UNIVERSITY ECE DEPARTMENT, COLLEGE OF ENGINEERING 98. The shunt resistance in a PMMC ammeter __ as the current range is increased. A. Decreases * B. Is zero C. Is open D. Increases 99. A LED is tested using a PMMC ohmmeter such that the positive lead is at the anode of the LED and the other lead is at the other end. The LED is __ and the ohmmeter deflection angle is __. A. OFF, big B. OFF, small C. ON, big * D. ON, small 100. Assertion (A): The scale a PMMC ammeter is linear. Reason (R): The deflecting torque of PMMC is proportional to current in the coil. A. Both A and R are true and R is correct explanation of A * B. Both A and R are true but R is not correct explanation of A C. A is true R is false D. A is false R is true