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ECE Board Exam Reviewer: ELECTRONICS Part 3
1. The collector current is simply Beta times the _____. a. Base current c. Gate current b. Alpha d. Emitter current
2. When the input signal is applied to the base and the output is obtained at the collector, what is the transistor
configuration where emitter acts as the common? a. Common-‐collector c. Common-‐base b. Common-‐emitter d. None of the above
3. The transistor configuration common-‐base and common-‐emitter have the same output terminal at?
a. Drain c. Source b. Base d. Collector
4. When alpha is approximately equal to 1, it is assumed that the _____ is so small that it can be ignored to
compute the operating point. a. Emitter current c. Base current b. Collector current d. None of the above
5. It is a two terminal device referred sometimes as hot-‐carrier diode or surface-‐barrier diode. a. Photodiode c. Schottky diode b. Transistor d. Varactor diode
6. The maximum current (rms) and power (gate) ratings for commercially available _____ are about 3A and 0.1W,
respectively. a. Diac c. Triac b. LASCR d. Shockley diode
7. It is a device that contains both an infrared LED and a photodetector such as silicon diode, transistor, Darlington pair, or SCR. a. Optoisolators c. Photodiode b. Thermistor d. SCR
8. The secondary voltage of a _____ transformer is lower than primary voltage.
a. Rectifiers c. Step-‐down b. Power supply d. Step-‐up
9. An RC snubber protects an SCR against ______.
a. Supply overvoltages c. Breakover b. False triggering d. Crowbarring
10. Which has the greatest holding strength? a. Electric c. Thermal b. Pneumatic d. Hydraulic
11. It is known as the common-‐emitter forward amplification factor. a. Gamma-‐ratio c. Alpha-‐ratio b. Beta-‐ratio d. None of the above
12. A modulation technique that generates variable-‐width pulses to represent the amplitude of an analog input
signal. a. Switching power supply c. Buck converters b. Boost regulators d. Pulse with modulation
13. Buck converter has characteristic where the output voltage is always _____ than the input voltage.
a. Equal c. Lower b. Greater d. Higher
14. For high-‐speed integrated circuits, which semiconductor material given is best to be used?
a. Silicon c. Germanium b. Gallium arsenide d. Gallium phosphide
15. The restriction of certain discrete energy levels in a semiconductor material can be predicted generally by using?
a. Bohr model c. Bode plot b. Lenz’s law d. Gauss law
16. In applications where a high torque is needed during starting, this motor is preferable _____.
a. DC shunt c. AC motor b. Stepper motor d. DC series
17. When VGG supplies the gate of an N-‐channel MOSFET with a positive voltage, the device is operating in the
_____ mode. a. Depletion c. Both A & B b. Enhancement d. None of the above
18. A type of MOSFET which has advantages of very high input impedance, fast switching speeds, and low operating
power levels and it is very useful in logic circuits. a. VMOS c. CMOS b. MESFET d. JFET
19. The drain current of an enhancement-‐type MOSFET is 0mA when the values of VGS less than the _____.
a. Cut-‐off frequency c. A & B b. Threshold level d. None of the above
20. A very popular connection of two bipolar junction transistors for operation as one ‘’superbeta’’ transistor
a. Cascode c. Feedback Pair b. Darlington d. None of the above
21. The ac analysis of of JFETs and depletion-‐type MOSFETS is _____.
a. difficult c. different b. same d. none of the above
22. There is no _____ between the input and output for the source-‐follower and common-‐gate configurations.
a. Current c. Voltage b. Power d. Phase shift
23. When the VGS is one-‐half the _____ value, gm is one-‐half the maximum value.
a. Power c. Pinch-‐off b. Impedance d. None of the above
24. Which of the following characterizes inductance?
a. Tends to oppose dc c. Tends to oppose changes in voltage b. Tends to oppose changes in current d. Opposes all frequencies equally
25. Permeability is the _____.
a. Power found in the electromagnet c. Power found in the transformer b. Power found in the magnetic field d. Ease with which metals maybe magnetized/demagnetized
26. If the secondary of a transformer is stepped down, the primary will have
a. Less turns c. Half as many turns b. Twice as many turns d. More turns
27. Power transformers are usually rated in _____.
a. kwh b. kw c. kva d. ampere-‐turn
28. What type of transformer is used to protect technicians from deadly electrical shock?
a. Isolation transformer c. Step-‐up transformer b. Absorber transformer d. Step-‐down transformer
29. A step-‐up transformer _____.
a. Decreases voltage and amperage b. Raises voltage and amperage c. Raises voltage and decreases amperage d. Decreases voltage and increases amperage
30. What condition exists if the anode and cathode of a cell are connected together without a load?
a. Short circuit c. Grounded circuit b. Overload d. No load
31. _____ refers to the majority carrier in N-‐type semiconductor.
a. hole c. negative ion b. positive ion d. electron
32. The base SI unit of luminous intensity is a. Lux c. Lambert b. Lumen d. Candela
33. What phenomenon in electronics does an avalanche breakdown primarily dependent?
a. Doping c. Ionization b. Collision d. Recombination
34. Which is the principal characteristic of a varactor diode?
a. It has a very high PIV b. It has a negative region c. Its internal capacitance varies with the applied voltage d. It has a constant voltage under conditions of varying current.
35. _____ is the region in a transistor that is heavily doped.
a. Collector c. Emitter b. Ground d. Base
36. The term cut-‐off for a transistor refers to _____.
a. The transistor is at its operating point b. No current flow from emitter to collector c. Maximum current flow from emitter to collector d. There is no base current
37. A transistor acts as _____ when saturated. a. Open circuit c. Very high resistance b. Very low resistance d. Variable resistance
38. What is the most stable type of biasing?
a. Current feedback c. Voltage divider b. Fixed bias d. Voltage feedback
39. The type of bias used where only moderate changes in ambient temperature are expected?
a. Combination bias c. Self-‐bias b. Fixed bias d. Limited bias
40. Which class of amplifier has the highest linearity and least distortion?
a. Class A c. Class C b. Class B d. Class D
41. The output resistance in a common-‐base amplifier is _____.
a. Zero c. Low b. Medium d. High
42. In a MOSFET , the process of creating a channel or increasing the conductivity of the channel by the addition of charge carriers is called _____. a. Inducement c. Improvement b. Enhancement d. Balancing
43. When negative feedback is applied to an amplifier, its voltage gain
a. Is increased c. Remains the same b. Is decreased d. Becomes zero
44. The voltage between the input terminals of an ideal op-‐amp is _____.
a. Very small c. Zero b. Very large d. Equal to the input voltage
45. _____ is the progressive decay with time in the amplitude of the free oscillation in a circuit.
a. Decrement c. Damping b. Pulse decay in time d. Transient
46. What is the oscillator of a radar receiver?
a. Klystron oscillator c. Detector b. Hartley oscillator d. Product detector
47. _____ is the property of a crystal by which mechanical forces produce electrical charges and, conversely,
electrical charges produce mechanical forces a. Damping c. Doppler effect b. Flywheel effect d. Piezoelectric effect
48. A system in which the precise movement of a large load is controlled by a relatively weak signal.
a. Hydraulic c. Servo b. Electric d. Synchro
49. The _____ are two of the most common mechanical configurations of industrial robots.
a. Spherical and pneumatic c. Cylindrical and hydraulic b. Spherical and hydraulic d. Articulated arm and cylindrical
50. Who developed resistance welding in 1886?
a. Isaac Asimov c. Isaac Newton b. Elihu Thomson d. JJ Thomson
51. What do you call the ration between the intensity of magnetization produced in a substance, to the source of the magnetizing force.
a. magnetic reluctivity c. magnetic resisitivity b. magnetic conductivity d. magnetic susceptibility
52. Coercive force is typically expressed in a. oersteds c. gilberts b. Maxwell d. gauss
53. The transfer of energy from one circuit to another circuit by electromagnetic induction is called a. transformation c. coupling action b. matching action d. transformer action 54. _________ is the unit of reluctance. a. Maxwell c. Weber b. At/Wb d. Gauss 55. An atom that contains 6 protons and 5 electrons has what electrical charge? a. positive b. negative c. intermediate d. neutral 56. A three terminal resistor with one or more sliding contacts which functions as an adjustable voltage divider. a. rheostat c. bleeder resistor b. potentiometer d. voltage divider 57. When resistors are connected in series, what happens? a. Nothing c. the tolerance decreased b. the effective increased is increased d. the effective resistance is decreased 58. If the bands on a resistor are red, red, orange silver, what is the resistance value? a. 220 ohms 5% tolerance c. 223 ohms 10% tolerance b. 22,000 ohms 10% tolerance d. 2200 ohms 20% tolerance 59. As the American Wire Gauge number increases, the cross sectional area of the wire _________.
a. stays the same c. increases b. decreases d. remains neutral
60. Resistor with colored bands in the body a. adjustable resistor c. wire wound resistor b. variable resistor d. carbon compound resistor 61. The time constant of an inductive circuit is defined as the ratio of a. R/L c. √R/L b. L/R d. √L/R 62. The effect of doubling the number of turns in a coil on the inductance of the coil is ______ a. increases inductance c. no inductance b. same inductance d. reduces inductance 63. Which of the following factors will not effect the inductance of a coil? a. diameter of the coil c. core material used b. number of coil turns d. conductor tensility 64. The direction of the counter emf produced by an inductor is explained by a. Lenz’s Law c. Faraday’s Law b. Gauss Law d. Ampere’s Law 65. The left hand rule for generators states that the thumb of the left hand points in the direction of the motion of the ________.
a. magnetic field c. induced current b. generator poles d. conductor
66. Doubling the frequency that is applied to the capacitor a. doubles the reactance b. reduces the reactance c. cuts the reactance in half d. has no effect
67. A ______ is a component that is constructed y placing a thin slice of quartz between two metal plates for the purpose of precision oscillation. a. crystal c. chip b. piezoelectric diode d. cage 68. The objective of a capacitor is to ________ a. Store AC Current c. block AC current and pass DC current b. block DC current and pass AC current d. block AC current 69. A magnetic field is a/an _______ field. a. electrostatic c. energy b. dielectric d. force 70. Electrostatic lines of force radiate from a charge particle along what type of lines? a. curved lines c. orbital lines c. elliptical lines d. straight lines 71. A circuit with little or no resistance is called _______ a. voltage drop c. short circuit b. open circuit d. infinite circuit 72. What type of circuit breaker can be overridden if the operating mechanism is held on? a. emergency c. standard c. trip free d. nontrip free 73. This refers to the voltage induced in the conductor moving in a magnetic field is proportional to the rate at which the conductor cuts magnetic lines of force. a. Faraday’s Law c. Fermat’s Law b. Hall Effect d. Wiegand Effect 74. An electromagnetic wave will take a path that involves the least travel time when propagating between two points a. Seebeck Effect c. Fermat’s Principle b. Faraday’s Effect d. Gauss principle 75. This law states that charges generate electric fields. a. Gauss Law c. Faraday’s Law c. Lenz Law d. Amperes’Law 76. According to this law “ The force attraction or repulsion between two magnetic poles is directly proportional to their strengths”. a. Newton’s Universal Law of Gravitation c. Faraday’s Law b. Coulomb’s First Law d. Coulomb’s Second Law
77. The force attraction or repulsion between two poles is inversely proportional to the square of the distance between them. a. Faraday’s First Law c. Newton’s first Law b. Coulomb’s Second Law d. Asimov’s Second Law 78. The value of sine wave of voltage or current at one particular instant of time. a. average value c. effective value b. RMS value d. instantaneous value 79. The _____ of angle theta is the power factor
a. sine c. cosine b. tangent d. cotangent
80. The power dissipated across the resistance in an AC circuit a. inactive power c. real power b. reactive power d. apparent power 81. The form factor of DC is a. zero c. unity b. 0.5 d. infinite 82. Rust in electrical wire connections will result to ____________. a. conductance c. resistance b. voltage d. inductance 83. A power factor of 1 indicates that a circuit is a. purely reactive c. purely XC b. purely resisitive d. purely XL
84. __________ is a parallel LC circuit. a. Hartley Circuit c. Static Circuit b. Tank circuit d. parallel resisting circuit 85. The net reactance in a RLC circuit is a. XL c. XC-‐ XL b. XL-‐ XC d. XC
86. Holes act like a. atoms c. crystals b. negative charges d. positive charges 87. Types of impurities in p type semiconductor like boron and gallium a. covalent c. bivalent b. pentavalent d. trivalent
88. If the load resistance decreases in a zener regulator, the zener current a. decreases c. stays the same b. increases d. equals the source voltage divided by the series resistance 89. The capacitance of a varactor diode increases when the reverse voltage across it a. decreases c. increases b. breaks down d. stores charges 90. Avalanche breakdown is primariliy dependent on the phenomenon of
a. doping c. collision b. recombination d. ionization
91. A/ an __________ is a device that houses a light emitter and a light sensor in the same package a. optpcoupler c. oscillator b. optoisolator d. a or b 92. What type of coupling would be most useful for an audio amplifier between the first and second stage? a. impedance c. RC b. transformer d. Resistor 93. The primary difference between a PNP and NPN amplifier. a. Capacity c. type of input b. type of bias d. polarity of source voltage 94. When operated in cut off and saturation, a transistor acts like a ____ a. switch c. linear amplifier b. variable capacitor d. variable resistor 95. The cutoff region of transistor characteristic curves is useful for a. digital switching applications c. filter applications b. analog switching application d. amplifier application 96. If Ic is 50 times larger than IB, then beta is a. 500 c. 0.02 d. 100 d. 50 97. If line frequency of 60 Hz, the output frequency of a half wave rectifier is _____ a. 30 Hz c. 60 Hz b. 120 Hz d. 240 Hz 98. If no current flows through the load in a bridge circuit, this is called a bridge ___________ a. leaky c. critical c. unstable d. balanced 99. The d’Arsonval Meter is really a/an
a. DC voltmeter c. AC ammeter b. AC voltmeter d. DC ammeter
100. A triac behaves like two a. diodes in series c. resistor and one diode b. four layer diodes in parallel d. inverse parallel SCRs connected with common gate 101. If a load resistance is 1 kohm, a stiff voltage source has a resistance of
a. At least 10 ohm b. Less than 10 ohm
c. More than 100 kohm d. Less than 100 kohm
102. The Thevenin voltage is the same as the
a. Shorted-‐load voltage b. Open-‐load voltage
c. Ideal source voltage d. Norton voltage
103. An ideal voltage source and an internal resistance is an example of the
a. Ideal approximation b. Second approximation
c. Higher approximation d. Exact model
104. The voltage out of an ideal voltage source
a. Is zero b. Is constant
c. Depends on the value of load resistance d. Depends on the internal resistance
105. Thevenin’s theorem replaces a complicated circuit facing a load by an
a. Ideal voltage source and parallel resistor b. Ideal current source and parallel
resistor
c. Ideal voltage source and series resistor d. Ideal current source and series resistor
106. Norton’s theorem replaces a complicated circuit facing a load by an a. Ideal voltage source and parallel resistor b. Ideal current source and parallel resistor
c. Ideal voltage source and series resistor d. Ideal current source and series resistor
107. Each valence electron in an intrinsic semiconductor establishes a
a. Covalent bond b. Free electron
c. Hole d. Recombination
108. The merging of a free electron and a hole is called
a. Covalent bonding b. Lifetime
c. Recommendation d. Thermal energy
109. A conductor has how many types of flow?
a) 1 b) 2
c) 3 d) 4
110. A semiconductor has how many types of flow?
a. 1 b. 2
c. 3 d. 4
111. In an intrinsic semiconductor, the number of free electrons
a. Equals the number of holes b. Is greater than the number of holes
c. Is less than the number of holes d. None of the above
112. The number of free electrons and holes in an intrinsic semiconductor increases when the temperature a. Decreases b. Increases
c. Stays the same d. None of the above
113. Diffusion of free electrons across the junction of an unbiased diode produces
a. Forward bias b. Reverse bias
c. Breakdown d. The depletion layer
114. The voltage where avalanche occurs is called the
a. Barrier potential b. Depletion layer
c. Knee voltage d. Breakdown voltage
115. Surface-‐leakage current is part of the
a. Forward current b. Forward breakdown
c. Reverse current d. Reverse breakdow
116. In a silicon diode the reverse current is usually a. Very small b. Very large
c. Zero d. In the breakdown region
117. How much voltage is there across the second approximation of a silicon diode when it is forward biased? a. 0 b. 0.3 V
c. 0.7 V d. 1 V
118. With a full-‐wave rectified voltage across the load resistor, load current flows for what part of a cycle?
a. 0 degrees b. 90 degrees
c. 180 degrees d. 360 degrees
119. If the filtered load current is 10 mA, which of the following has a diode current of 10 mA?
a. Half-‐wave rectifier b. Full-‐wave rectifier
c. Bridge rectifier d. Impossible to say
120. If the secondary voltage increases in a bridge rectifier with a capacitor-‐input filter, the load voltage will
a. Decrease b. Stay the same
c. Increase d. None of these
121. The load voltage is approximately constant when azener diode is a. Forward-‐biased b. Reverse-‐biased
c. Operating in the breakdown region d. Unbiased
122. The voltage across the zener resistance is usually a. Small b. Large
c. Measured in volts d. Subtracted from the breakdown voltage
123. When the source voltage increases in a zener regulator, which of these currents remains approximately constant?
a. Series current b. Zener current
c. Load current d. Total current
124. A photodiode is normally
a. Forward-‐biased b. Reverse-‐biased
c. Neither forward-‐ nor reverse-‐biased d. Emitting light
125. When the light increases, the reverse minority carrier current in a photodiode a. Decreases b. Increases
c. Is unaffected d. Reverses direction
126. The varactor is usually
a. Forward-‐biased b. Reverse-‐biased
c. Unbiased d. Operated in the
breakdown region 127. Most of the electrons in the base of an npn transistor flow
a. Out of the base lead b. Into the collector
c. Into emitter d. Into the base supply
128. In a normally biased npn transistor, the electrons in the emitter have enough energy to overcome the barrier potential of the
a. Base-‐emitter junction b. Base-‐collector junction
c. Collector-‐base junction d. Recombination path
129. What is the most important fact about the collector current? a. It is measured in milliamperes. b. It equals the base current divided by
the current gain.
c. It is small d. It approximately equals the emitter
current. 130. The graph of current gain versus collector-‐current indicates that the current gain
a. Is constant b. Varies slightly
c. Varies significantly d. Equals the collector current divided by
the base current
131. Three different Q points are shown on a load line. The upper Q point represents the a. Minimum current gain b. Intermediate current gain
c. Maximum current gain d. Cutoff point
132. For emitter bias, the voltage at the emitter is 0.7 V less than the a. Base voltage b. Emitter voltage
c. d. Ground Voltage d. Collector voltage
133. If the emitter resistance doubles in a VDB circuit, the collector current will a. Double b. Drop in half
c. Remain the same d. Increase
134. The regulator with the highest efficiency is the
a. Shunt regulator b. Series regulator
c. Switching regulator d. NOTA
135. If the load is shorted, the pass transistor has the least power dissipation when the regulator has
a. Foldback limiting b. Low efficiency
c. Buck topology d. A high zener voltage
136. An advantage of shunt regulation is a. Built-‐in short-‐circuit protection b. Low power dissipation in the pass
transistor
c. High efficiency d. Little wasted power
137. To turn on a current booster, we can drive its base emitter terminals with the voltage across
a. A load resistor b. A zener impedance
c. Another transistor d. A current-‐sensing resistor
138. If a linear three-‐terminal IC regulator is more than a oscillations inside the IC unless you use a. Current limiting b. A bypass capacitor on the input pin
c. A coupling capacitor on the output pin d. A regulated input voltage
139. Compared to the ripple into a voltage regulator, the ripple out of a voltage regulator is
a. Equal in value b. Much larger
c. Much smaller d. Impossible to determine
140. The quantity that remains constant in a pulse-‐width modulator is
a. Pulse width b. Period
c. Duty cycle d. Space
141. An oscillator always needs an amplifier with
a. Positive feedback b. Negative feedback
c. Both types of feedback d. An LC tank circuit
142. The op-‐amp integrator uses
a. Inductors b. The Miller effect
c. Sinusoidal inputs d. Hysteresis
143. If pulse width decreases and the period stays the same, the duty cycle
a. Decreases b. Stays the same
c. Increases d. Is zero
144. The region between the passband and the stopband is called the
a. Attenuation b. Center
c. Transition d. Ripple
145. If an op amp has only a positive supply voltage, its output cannot
a. Be negative b. Be zero
c. Equal the supply voltage d. Be ac coupled
146. In the classic three op-‐amp instrumentation amplifier, the differential voltage gain is usually produced by the
a. First stage b. Second stage
c. Mismatched resistors d. Output op amp
147. The input signal for an instrumentation amplifier usually comes from
a. An inverting amplifier b. A transducer
c. A differential amplifier d. A Wheatstone bridge
148. In an ac amplifier using an op amp with coupling and bypass capacitors, the output offset voltage is a. Zero b. Minimum
c. Maximum d. Unchanged
150. Negative feedback does not improve
a. Stability of voltage gain b. Nonlinear distortion in later stages
c. Output offset voltage d. Power bandwidth
151. The input impedance of a current-‐to-‐voltage converter is
a. Small b. Large
c. Ideally zero d. Ideally infinite
152. When an op amp is not saturated, the voltages at the non-‐inverting and inverting inputs are
a. Almost equal b. Much different
c. Equal to the output voltage d. Equal to +15 V
153. If the frequency is greater than the power bandwidth,
a. Slew-‐rate distortion occurs b. A normal output signal occurs
c. Output offset voltage increases d. Distortion may occur
154. The open-‐loop cutoff frequency of a 741C is controlled by a. A coupling capacitor b. The output short circuit current
c. The power bandwidth d. A compensating capacitor
155. The input impedance of a BIFET op amp is
a. Low b. Medium
c. High d. Extremely high
156. At the unity-‐gain frequency, the open-‐loop voltage gain is
a. 1 b. Amid
c. Zero d. Very large
157. What usually controls the open-‐loop cutoff frequency of an op amp?
a. Stray-‐wiring capacitance b. Base-‐emitter capacitance
c. Collector-‐base capacitance d. Compensating capacitance
158. With both bases grounded, the only offset that produces an error is the a. Input offset current b. Input bias current
c. Input offset voltage d. NOTA
159. When the two bases are grounded in a diff amp, the voltage across each emitter diode is
a. Zero b. 0.7 V
c. The same d. High
160. The common-‐mode rejection ratio is a. Very low b. Often expressed in decibels c. Equal to the voltage gain
d. Equal to the common-‐mode voltage gain
161. The common-‐mode voltage gain is
a. Smaller than voltage gain b. Equal to voltage gain
c. Greater than voltage gain d. None of the above
162. Monolithic ICs are
a. Forms of discrete circuits b. On a single chip
c. Combinations of thin-‐film and thick-‐film circuits
d. Also called hybrid ICs 163. If you want to improve the high-‐frequency response of an amplifier, which of these would you try?
a. Decrease the coupling capacitances. b. Increase the emitter bypass capacitance.
c. Shorten leads as much as possible. d. Increase the generator resistance.
164. At low frequencies, the coupling capacitors produce a decrease in
a. Input resistance b. Voltage gain
c. Generator resistance d. Generator voltage
165. Any thyristor can be turned off with
a. Breakover b. Forward-‐bias triggering
c. Low-‐current drop out d. Reverse-‐bias triggering
166. A SCR is usually turned on by
a. Breakover b. A gate trigger
c. Breakdown d. Holding current
167. The minimum anode current that keeps a thyristor turned on is called the
a. Holding current b. Trigger current
c. Breakover current d. Low-‐current drop out
168. The minimum input current that can turn on a thyristor is called the
a. Holding current b. Trigger current
c. Breakover current d. Low-‐current drop out
169. A thyristor can be used as
a. A resistor b. An amplifier
c. A switch d. A power source
170. Most small-‐signal E-‐MOSFETs are found in
a. Heavy-‐current applications b. Discrete circuits
c. Disk drives d. Integrated circuits
171. The main advantage of CMOS is its
a. High power rating b. Small-‐signal operation
c. Switching capability d. Low power consumption
172. With active-‐load switching, the upper E-‐MOSFET is a
a. Two-‐terminal device b. Three-‐terminal device
c. Switch d. Small resistance
173. An ordinary resistor is an example of
a. A three-‐terminal device b. An active load
c. A passive load d. A switching device
174. Which of these may appear on the data sheet of an enhancement-‐mode MOSFET? a. VGS(th) b. ID(on)
c. VGS(on) d. All of the above
175. The voltage that turns on an EMOS device is the
a. Gate-‐source cutoff voltage b. Pinchoff voltage
c. Threshold voltage d. Knee voltage
176. Transconductance indicates how effectively the input voltage controls the
a. Voltage gain b. Input resistance
c. Supply voltage d. Output current
177. Transconductance is measured in
a. Ohms b. Amperes
c. Volts d. Mhos or Siemens
178. When the gate voltage becomes more negative in an n-‐channel JFET, the channel between the depletion layers
a. Shrinks b. Expand
c. Conduct d. Stop conducting
179. A cascode amplifier has the advantage of
a. Large voltage gain b. Low input capacitance
c. Low input impedance d. Higher gm
180. The input signal used with a JFET analog switch should be
a. Small b. Large
c. A square wave d. Chopped
181. The gate-‐source diode of a JFET should be a. Forward-‐biased b. Reverse-‐biased
c. Either forward-‐ or reverse-‐biased d. None of the above
182. Compared to a bipolar transistor, the JFET has a much higher
a. Voltage gain b. Input resistance
c. Supply voltage d. Current
183. The pinchoff voltage has the same magnitude as the
a. Gate voltage b. Drain-‐source voltage
c. Gate-‐source voltage d. Gate-‐source cutoff voltage
184. When the drain saturation current is less than IDSS, a JFET acts like a a. Bipolar transistor b. Current source
c. Resistor d. Battery
185. RDS equals pinchoff voltage divided by the
a. Drain current b. Gate current
c. Ideal drain current d. Drain current for zero gate voltage
186. The transconductance curve is a. Linear b. Similar to the graph of a resistor
c. Nonlinear d. Like a single drain curve
187. The transconductance increases when the drain current approaches
a. 0 b. ID(sat)
c. IDSS d. IS
188. The input impedance of a JFET
a. Approaches zero b. Approaches one
c. Approaches infinity d. Is impossible to predict
189. A JFET
a. Is a voltage-‐controlled device b. Is a current-‐controlled device
c. Has a low input resistance d. Has a very large voltage gain
190. The ac emitter resistance of an emitter follower
a. Equals the dc emitter resistance b. Is larger than the load resistance
c. Has no effect on MPP d. Is usually less than the load resistance
191. For a class B push-‐pull emitter follower to work properly, the emitter diodes must
a. Be able to control the quiescent current b. Have a power rating greater than the
output power
c. Have a voltage gain of I d. Match the compensating diodes
192. A small quiescent current is necessary with a class B push-‐pull amplifier to avoid
a. Thermal runaway b. Destroying the compensating diodes c. Crossover distortion d. Excessive current drain
193. The zener current in a zener follower is
a. Equal to the output current b. Smaller than the output current
c. Larger than the output current d. Prone to thermal runaway
194. The transistors of a class B push-‐pull emitter follower are biased at or near
a. Cutoff b. The center of the dc load line
c. Saturation d. The center of the ac load line
195. Thermal runaway is
a. Good for transistors b. Always desirable
c. Useful at times d. Usually destructive
196. Usually, the distortion in an emitter follower is
a. Very low b. Very high
c. Large d. Not acceptable
197. A square wave out of an emitter follower implies
a. No clipping b. Clipping at saturation
c. Clipping at cutoff d. Clipping on both peaks
198. If the load resistance of an emitter follower is very large, the external ac emitter resistance equals a. Generator resistance b. Impedance of the base
c. DC emitter resistance d. DC collector resistance
199. The current drain of an amplifier is the
a. Total ac current from the generator b. Total dc current from the supply
c. Current gain from base to collector d. Current gain from collector to base
200. The instantaneous operating point swings-‐along the
a. AC load line b. DC load line
c. Both load lines d. Neither load line
201. Compared to the ac resistance of the emitter diode, the feedback resistance of a swamped amplifier should be
a. Small b. Equal
c. Large d. Zero
202. The emitter is at ac ground in a
a. CB stage b. CC stage
c. CE stage d. None of these
203. The ac collector current is approximately equal to the
a. AC base current b. AC emitter current
c. AC source current d. AC bypass current
204. The capacitor that produces an ac ground is called a
a. Bypass capacitor b. Coupling capacitor
c. Dc open d. Ac open
205. The current in a coupling circuit for high frequencies is
a. Zero b. Maximum
c. Minimum d. Average
206. A coupling capacitor is
a. A dc short b. An ac open
c. A dc open and an ac short d. A dc short and an ac open
207. For dc, the current in a coupling circuit is
a. Zero b. Maximum
c. Minimum d. Average
208. The currents of a pnp transistor are
a. Usually smaller than npn currents b. Opposite npn currents
c. Usually larger than npn currents d. Negative
209. The majority carriers in the emitter of a pnp transistor are
a. Holes b. Free electrons
c. Trivalent atoms d. Pentavalent atoms
210. Which is the largest current in a pnp transistor? a. Base current b. Emitter current
c. Collector current d. None of these
211. The easiest way to bias a JFET in the ohmic region is with
a. Voltage-‐divider bias b. Self-‐bias
c. Gate bias d. Source bias
212. An English mathematician who invented the slide rule in 1622. A. Blaise Pascal C. Charles Babage B. Clifford Berry D. William Oughtred 213. Built a computer in 1946 at the Institute of Advance Study (IAS), Princeton, USA, that uses binary numbers and stores information. A. Vannever Bush C. John Atannasoff B. John Van Neumann D. Clifford Berry 214. An electronic device design to accept data performs prescribe computational and logical operations at high speed and output the results of this operation. A. Compiler C. Computer B. Simulator D. Digital Machine 215. The code 1011 in BCD is A. 24 C. 11 B. letter A D. invalid 216. First commercial computer introduced in 1953 that uses valves. A. IBM-‐1400 C. IBM-‐701 B. UNIVAC D. ENIAC 217. The first electronic computer and was completed in 1946. A. ENIAC C. EDVAC B. UNIVAC D. Whirlwind I 218. ENIAC was developed at A. University of Pennsylvania C. Cambridge University B. Massachusetts Institute of Technology D. Bell Laboratories 219. ENIAC consist of how many vacuum tubes? A. 1,500 tubes C. 13,575 tubes B. 3,575 tubes D. 18,000 tubes 220. Refers to the increased use of data conversion circuits as a result of increased application. A. Op Amps C. Computers B. Linear Circuit D. Digital Equipment
221. Which one of the following statement is FALSE ? a. The resistance of intrinsic semiconductor decreases with increase of temperature b. Pure Si doped with trivalent impurities gives a p-‐type semiconductor c. Majority carriers in a n-‐type semiconductor are holes d. Minority carries in a p-‐type semiconductor are electrons
222. What is a group of circuits that provides timing and signals to all operation in the computer? A. Output unit C. Control unit B. Memory unit D. Input unit 223. What does ALU which carries arithmetic and logic operations process? A. Binary Coded Decimal C. Octal numbers B. Hexadecimal numbers D. Binary numbers 224. What is the smallest part of a computer language? A. binary C. bit B. byte D. word 225. A digital word consisting of only four bits is called a A. dibit C. pixel B. quad D. nibble 226. How many symbols does hexadecimal digital number system used? A. 16 C. 8 B. 4 D. 32 227. How many symbols are used octal digital number system? A. 16 C. 8 B. 4 D. 2 228. What is the relationship between current (I) and voltage (E) in a circuit consisting of a capacitor in series with a resistor?
a. I and E are in phase across the capacitor. c. E leads I across the capacitor. b. I leads E across the resistor. d. I and E are in phase across the resistor
229. Which of the following is not used in hexadecimal digital symbols? A. A C. H B. C D. F 230. Mathematics used in expressing, analyzing, and designing of digital electronic circuits. A. Boolean algebra C. statistical approach B. numerical methods D. logical mathematics 231. What level is used to represent logic 1 in a negative logic circuit? A. negative transition level C. positive transition level B. low level D. high level
232. What level is used to represent logic 0 in a negative logic circuit? a. high level c. negative transition level b. low level D. Positive transition level 233. Why is it important to maintain an impedance match from the source to the load when sending signals?
a. to reduce external noise c. to reduce reflected energy b. to keep the line balanced d. to reduce attenuation
234. Because solid state diodes have no filament, they a. don't work. c. require less operating power. b. are less efficient than tubes. d. require more operating power.
235. Holding resistance constant, how does increasing current in a circuit affect voltage?
a. current increases c. voltage increases b. current decreases d. voltage decreases
236. A solid stat device which only gives a “1” output if all inputs are also “1” is called a. an AND gate c. a NOR gate b. a NAND gate d. an OR gate 237. In a closed electrical circuit,
a. one terminal is always positive, c. both terminals can be negative. and one terminal is always negative. b. both terminals can be positive. d. terminals are neither positive nor negative.
238. _______refers to the class of logic circuit containing flip-‐flops. A. Combinational C. Linear B. Sequential D. Feedback 239. To convert DC to AC, which device is used?
a. converter c. diode b. transformer d. regulator
240. ________is called the time sharing of one line with multiplex signals. A. Simultaneous transmission C. Relay B. Bi-‐directional D. Multiplexing 241. Data selector is also called A. encoder C. multiplexer B. decoder D. demultiplexer 242. A high traffic connectivity portion of any communications network. In packet-‐switched networks, a primary forward direction path traced sequentially through two or more major relay or switching stations. In packet-‐switched networks, a backbone consists primarily of switches and inter-‐switch trunks.
a.backone b. background noise c.back resistance d.back shell.
243. The total system noise in the absence of a signal [information transmission]. a. backone c. back shell b. back resistance d. background noise
244.The rear portion of a connector. a .backone b. back shell c. back resistance d. background noise
245. The larger resistance value observed when you are checking the resistance of a semiconductor. a. backone b. back shell c. back resistance d. background noise
246. A Push-‐Pull Amplifier. a. balanced code c. balanced bridge b. balanced amplifier d. balanced line
247. A bridge circuit adjusted to produce a zero output. a. balanced code c. balanced bridge b. balanced amplifier d. balanced line
248. A cable or circuit having two identical conductors with the same electromagnetic characteristics in relation to other conductors and to ground, as in a pair of conductors. A twisted pair line
a. balanced code c. balanced bridge b. balanced amplifier d. balanced line
249. In PCM systems, a code constructed so that the frequency spectrum resulting from the transmission of any code word has no DC component. A code that has a finite digital sum variation [PCM]. A number of additional terms are related, use the search bar, below right, to find the correct definition.
a. balanced code c. balanced bridge b. balanced amplifier d. balanced line
250. A test used to subject a component, device or system to extreme conditions to determine the useful life of the device under test.
a. accelerated life testing c. accelerometer b. accelerating anode d. acceleration servo system
251. An electrode charged several thousand volts positive and used to accelerate electrons toward the front of a Cathode-‐Ray Tube.
a . accelerated life testing c. accelerometer b .accelerating anode d. acceleration servo system
252. A servo-‐system that controls the acceleration (rate of change in velocity) of a load. a. accelerated life testing c. accelerometer b. accelerating anode d. acceleration servo system
253. A device that measures the acceleration to which it is subjected and develops a signal proportional to it. a. accelerated life testing c. accelerometer b. accelerating anode d. acceleration servo system
254. An impurity which, when added to a semiconductor, accepts one electron from a neighboring atom and creates a hole in the lattice structure of the crystal. Also called Trivalent Impurity.
a. accelerated life testing c. acceptor impurity b. acces time d. acceleration servo system
255. The difference in time between when data is requested and when data is delivered. The time lapsed between a given command and when the function is performed.
a. accelerated life testing c. acceptor impurity b. acces time d. acceleration servo system
256. A register that both stores a number and adds to other numbers loaded into the register. a. ac generator c. acorn tube b. accumulator d. acoustics
257. A very small tube with closely spaced electrodes and no base. The tube is connected to its circuits by short wire pins that are sealed in a glass or ceramic envelope. The acorn tube is used in low power uhf circuits. a. ac generator c. acorn tube b. accumulator d. acoustics
258. The science of sound. a. ac generator c. acorn tube b. accumulator d. acoustics
259. A rotating machine that converts mechanical energy into alternating current.
a. ac generator c. acorn tube b. accumulator d. acoustics
260. The unintended sound a component produces while operating. Some fields apply this to mean an audible sound, while other fields take it to mean any sound.
a. acoustic noise c. acorn tube b. accumulator d. acoustics
261. A component that draws current or some type of gain. a. active component c. active low b. active filter d. active pullup
262. Refers to an inverted output, the output is true when low and false when high. When the Sum-‐of-‐Products expression is true the output is low.
a. active component c. active low b. active filter d. active pullup
263. A transistor or FET used to pull a line high instead of a resistor. Active Pullups are common within ICs, but they are not designed to sink much current [weak pull-‐up].
a. active component c. active low b. active filter d. active pullup
264. A filter that uses an amplifier in addition to passive components. a . active component c. active low b. active filter d. active pullup
265. Refers to a non-‐inverted output, the output is true when high and false when low. When the Sum-‐of-‐Products expression is true the output is high.
a. active component b. active low b. active high d. active pullup
266. A cable that is ready for installation in specific applications and usually terminated with connectors. a. cable assembly c. cable clamp b. cable carrier d. cable, coaxial
267. A mechanical clamp attached to the wire entrance of a connector to support the cable or wire bundle, provide stress relief, and absorb vibration and shock.
a. cable assembly c. cable clamp b. cable carrier d. cable, coaxial
268. A cable in which an insulated conductor is centered inside another. The outer conductor is usually a metal braid or metal sheath. Braided cables usually have an outer insulating jacket over the braid. Coaxial cables are used primarily for transmission of RF signals.
a. cable assembly c. cable clamp b. cable carrier d. cable, coaxial
269. A device that holds a cable. Also refer to a detailed definition of Cable Carrier. In some case it may be called a cable retracter.
a. cable assembly c. cable clamp b. cable carrier d. cable, coaxial
270. A group of wires or ribbons of wiring used to interconnect electronic systems and subsystems. a. cable jacket c. cable clamp b. cable harness d. cable sheat
271. A conductive protective covering applied to cables. See the diagram for a Coax Cable with armor above.
a. cable jacket c. cable clamp b. cable harness d. cable sheat
272. The property of an electrical circuit that opposes changes in voltage. a. capacitance c. capacitor b. capacitive coupling d. capacitive reactance
273. The transfer of energy from one circuit to another by means of the mutual capacitance between the circuits. a. capacitance c. capacitor
b. capacitive coupling d. capacitive reactance
274. The opposition, expressed in ohms, offered to the flow of an alternating current by capacitance. a. capacitance c. capacitor b. capacitive coupling d. capacitive reactance
275. An electrical device capable of storing electrical energy in an electrostatic field. a. capacitance c. capacitor
b. capacitive coupling d. capacitive reactance
276. A sinusoidal wave in which the amplitude steadily decreases with time. Often associated with energy loss. a. capacitance c. damped wave
b. damping d. capacitive reactance
277. The process of smoothing out oscillations. The progressive decay with time in the amplitude of the free oscillations in a circuit.
a. capacitance c. damped wave b .damping d. capacitive reactance
278. The extent to which a functional unit focused at infinity, the far-‐field region is sometimes will continue to operate at a defined performance level even though one or more of its components are malfunctioning.
a.FEP c. FDDI b. fault tolerance d. feedback
279. Fiber Distributed Data Interface is a Local Area Network [LAN] using Fiber-‐Optic cable in a Dual Token Ring topology.
a.FEP c. FDDI b. fault tolerance d. feedback
280. The return of a portion of the output, or processed portion of the output, of a (usually active) device to the input. a.FEP c. FDDI b. fault tolerance d. feedback
281. Fluorinated Ethylene Propylene, A synthetic type of insulation. a.FEP b. FDDI b. fault tolerance d. feedback
282. A fiber optic component normally assembled onto a cable and attached to a piece of apparatus for the purpose of providing interconnecting/disconnecting of fiber optic cables.
a. Fiber optic connector c. fiber optic link b. fidelity d. fibrous braid
283. A communications link that transmits signals by means of modulated light propagated in an optical fiber. a. Fiber optic connector c. fiber optic link b. fidelity d. fibrous braid
284. An outer covering used to protect a conductor’s insulating material. Commonly made from cotton, linen, silk, rayon, or fiberglass.
a. Fiber optic connector c. fiber optic link b. fidelity d. fibrous braid
285. The faithful reproduction of a signal. The accuracy with which a system reproduces a signal at its output that faithfully maintains the essential characteristics of the input signal.
a. Fiber optic connector c. fiber optic link b. fidelity d. fibrous braid
286. Data flow in either direction, but not in both directions at the same time. There are a number of interface buses that only allow Half-‐Duplex operation, while some bus networks just add a redundant path in the opposite direction to allow communication in either direction at the same time.
a. half-‐wave rectifier c. half-‐wave voltage boubler b. half-‐duplex d. NOTA
289. A rectifier using only one-‐half of each cycle to change ac to pulsating dc.
a . half-‐wave rectifier c. half-‐wave voltage boubler b. half-‐duplex d. NOTA
290. Two half-‐wave voltage rectifiers connected to double the input voltage. a. half-‐wave rectifier c. half-‐wave voltage boubler b. half-‐duplex d. NOTA
291. A point on a waveform or radar beam that corresponds to half the power of the maximum power point. a. half-‐wave rectifier c. half-‐wave voltage boubler b. half-‐duplex d. NOTA
292. A frequency that is a whole-‐number multiple of a smaller base frequency. Of a sinusoidal wave, an integral multiple of the frequency of the wave. Harmonic percentages of a half sine wave; 2nd, 21.2%, 3rd, 0%, 4th 4.2%, 5th, 0% and 6th harmonic is 1.8%.
a.harmonic c. harmonic distortion b. acoustic d.NOTA
293. A ratio of 100 times the sum of all the harmonics to the fundamental. In the output signal of a device, distortion caused by the presence of frequencies that are not present in the input signal, caused by nonlinearities within the device.
a. harmonic c. harmonic distortion b. acoustic d. NOTA
294. The work done by a force of one newton acting through a distance of one meter. a. JTAG c. joule b. jitter d. NOTA
295. A “U” shaped opposite polarity material built a near JFET-‐channel center is called a. Gate c. Block
b. Drain d. Heat Sink 296. D-‐MOSFETs are sometimes used in series to construct a cascode high-‐frequency amplifier to overcome the loss of ______________. a. Low output impedance c. Capacitive reactance
b. High input impedance d. Inductive reactance
297. A MOSFET has how many terminals? a. 2 or 3 c. 4 b. 3 d. 3 or 4
298. When checking a good SCR or TRIAC with an ohmmeter it will: a. Show high resistance in both direction c. Show high resistance with positive on anode and negative on cathode
b. Show low resistance with positive d. Show low resistance in both direction on anode and negative on cathode 299. What does a hall effect sensor sense? a. Temperature c. Magnetic fields b. Moisture d. Pressure 300. What type of application would use a photovoltaic cell? a. An automobile horn c. A magnetic field detector b. A T1-‐92 calculator d. A remote power source
