This is the Section 2 Module 7 of the compiled Electronics Review Materials taken from different sources including but not limited to Electronics books, past Board Exams Questions, Journals and the Internet. This particular reviewer in Electronics Engineering has random Questions and Answers in random topics. Make sure to familiarize each questions to increase the chance of passing the ECE Board Exam.
Electronics Engineering Reviewers: Section 2 Module 7
Question |
Answer |
1. The purpose of offset nulling |
To zero the output error voltage |
2. A junction between two conductors that exhibits electrical characteristics under condition of changing temperature |
Thermoelectric Conjunction |
3. In electrical power distribution, what insulator is generally used? |
Porcelain |
4. Two essential parts in rotating generators |
Electro/permanent Magnet and Armature Winding |
5. An early version of the field effect transistor in which limited control of current carriers near the surface of a semiconductor bar or cell was obtained by an external electric field applied transversely |
Fieldistors |
6. Type of oscilloscope that are able to retain the display for a longer period |
Storage Oscilloscope |
7. Description used for generators trying to self-adjust its parameters before paralleling with online generators |
Jogging |
8. An op-amp has a common mode voltage gain of 10 and a differential mode voltage gain of 20,000. Calculate its CMRR |
2,000 |
9. The change in input offset current due to temperature change |
Input Offset Current Drift |
10. Which of the following characteristics does not necessarily apply to an op amp |
Low Power |
11. In an RL circuit, the ratio of inductive reactance over resistance, XL/R increases the phase angle |
Decreases |
12. Acoustic feedback in a public accurate system |
Serves no useful purpose |
13. What bridge is used to measure both inductances, capacitances, and impedances as high as frequencies |
Radio Frequency Bridge |
14. An op amp should have at least how many usable terminals? |
5 |
15. What term is applied to the use of two or more generators shared by a common load |
Parallel operation |
16. A 2 stage transistor amplifier whose output collector of the 1st stage provides input to the emitter of the 2nd stage. The final output is then taken from the collector of the 2nd stage. |
Cascode Configuration |
17. To make a basic instrumentation amplifier, it takes |
3 op-amps and 7 resistors |
18. High voltage is used in long distance power transmission because |
The I^2R losses are low |
19. The forward breakover voltage of a silicon diode is |
About 0.6 V |
20. The magnitude of the op amp’s input offset voltage before it gets classified as a low input offset voltage op amp should be |
0.2 mV |
21. Each atom in a silicon crystal has |
8 valence electron / 4 of its own and 4 shared |
22. A common base circuit is commonly employed as |
A radio frequency power amplifier |
23. Drain current in a constant current area increases when |
The gate to source voltage decreases |
24. Air works well as a dielectric mainly because it |
Has low loss |
25. When a semiconductor is reverse biased to a large enough voltage, it will conduct. The cause of this is |
Avalanche Effect |
26. Which one of the following is not an input/output of a 555 timer |
Clock |
27. The reason why a slight difference in the input bias current occurs in op amps is due to the unsymmetrical circuit component parameters. This unsymmetrical condition also produces a difference in input voltage called what? |
Input Offset Voltage |
28. This is a special bridge used in measuring very low resistance. The arrangement of the bridge reduces the effect of contact resistance which causes significant error in such low resistances when connected to low resistance bridges |
Kelvin Double Bridge |
29. What is an electronic instrument capable of showing on screen and may be on pen relative spacing of transmitter carriers, their sidebands, and harmonics |
Spectrum Analyzer |
30. The SCS differs from the SCR because |
It has 2 gate terminals |
31. Which FET has a wide and short effective channel |
V-MOSFET |
32. The maximum efficiency of a class AB amplifier is |
Slightly less than a class B |
33. In a wien-bridge oscillator, if the resistances of the positive feedback circuit are decreased the frequency |
Increases |
34. The frequency at which the open loop gain is equal to 1 is called |
Unity gain frequency |
35. Which of the following is not a characteristic of UJT |
Bilateral conduction |
36. The peak current that a class A amplifier can deliver to a load depends on the |
Quiescent Current |
37. What is the simplified version of the wheatstone bridge wherein two of the ratio arms are replaced by a 100 cm long manganin of uniform cross sections provided with a slider |
Slide wire bridge |
38. Substance which generates voltage when exposed to light |
Photovoltaic material |
39. A radio frequency oscillator usually |
Has most or all of its energy at a single frequency |
40. Which of the following resistor combinations provides lessened noise in an op amp circuit |
Make both the feedback and input resistances as small as possible |
41. The damping factor of a filter is set by |
Negative feedback circuit |
42. Generally, MOSFET have low power handling capability than BJTs, to increase the offset power the channel should be made |
Wide and short |
43. The characteristic that allows an isolation amplifier to amplify a small signal voltage in the presence of much greater noise voltages is its |
CMRR |
44. The main purpose of current limiting generator is |
Protection of the regulator from excessive current |
45. In the case of load regulation, when the load changes |
The output voltage stays constant |
46. A JFET circuit essentially never has |
Forward bias PN junction |
47. Generation of voltage in a generator can only happen when |
There is a relative motion between conducting wires and magnetic lines of force |
48. If a certain diode has a voltage of 3.6 volts, it operates in |
Zener breakdown |
49. Shifting the phase of an ac sine wave by 90 degrees |
Moving it to the right or left by ¼ cycle |
50. If two waves have the same frequency, the same phase, the composite wave |
Has a magnitude equal to the sum of two original waves |
51. In an exclusive OR gate the output is high only when |
The inputs have opposite logic states |
52. The stages of most isolation amplifiers are connected by |
Transformers |
53. Phase shift through an op-amp is caused by |
The internal RC circuit |
54. The frequency crystal oscillator junction is determined mainly by |
Thickness of the crystal |
55. Which of the following curves is the most useful |
Output characteristic curve |
56. The current consists mainly of holes and adjacent |
Has a p-type channel |
57. A circuit used for logic equalization on/off switching action of scr in series |
Nodder circuit |
58. Which bipolar amplifier type has some distortion in the signal wave with collector current during most but not all of the cycle |
Class AB-2 |
59. When you apply a triangular waveform to the input of a differential, the output is |
Square waveform |
60. The most popular op-amp packages are the metal can 8-pin DIP and the SMT, which of these corresponds to TO-99? |
Metal can |
61. Which of the following does not affect the inductance of the coil? |
The diameter of the wire |
62. A dc generator whose excitation is produced by a winding connected to its own positive and negative terminals |
Self excited shunt generator |
63. Generally, in dc generators the armature winding is rotated with respect to a stationary magnetic field is produced by |
permanent magnets or electromagnets |
64. The purpose of the I layer of the PIN diode is to |
Minimize diode capacitance |
65. SALLEN key filters are |
2nd order filters |
66. In an AND gate the output is high |
Only when all inputs are high |
67. Noise in the input comparator can cause the output to |
Change back and forth erratically between two states |
68. Which of the following bipolar transistor circuits can provide the most amplification |
Common emitter |
69. The difference between a series regulator and a shunt regulator is |
The type of sample circuit |
70. When choosing a motor for a particular application what characteristics should you consider? |
Speed, torque |
71. Which statement is true regarding alternators |
High speed alternators are smaller than low speed |
72. Generation of voltage in a generator can only happen |
When there Is relative motion between conducting wires and magnetic lines of force |
73. Of the values listed, the most realistic value for an open loop gain of an op-amp is |
100,000 |
74. An SCR differs from the 4-layer diode |
It has a gate terminal |
75. Push-pull amplifier that uses NPN and PNP transistors to amplify the positive and negative cycles respectively |
Complementary symmetry amplifier |
76. It consists of a single coil rotated in a magnetic field and produces an ac voltage |
Elementary generator |
77. Crossover distortion is a problem for |
Class B amplifier |
78. The operation of a logarithmic amplifier is based on |
The logarithmic characteristic of a PN junction |
79. What is the purpose of using a differential synchro than a regular synchro |
Differential synchro can handle more signals and can also perform addition/substraction function |
80. Once in saturation, a further increase in base current will |
Not affect the collector current |
81. The operation of a relaxation oscillator is based on |
Charging and discharging of the capacitor |
82. Synchronous type of ac motor |
Uses a dc generator to supply dc excitation to the rotating field |
83. What type of amplifier commonly used at the output stage of op-amps |
Complementary amplifier |
84. The purpose of installing thyrectors across the incoming power line to the speed control system is to |
Protect drive circuits from high voltage transient surges |
85. In a rectifier diode, current flows for how much of the ac cycle? |
180 degrees |
86. When a low pass and a high pass filter are cascaded with a band pass filter, the critical frequency of the low pass filter must be |
Greater than the critical frequency of a high pass filter |
87. When a voltage divider biased NPN transistor with the upper voltage divider resistor, the one connected to VCC opens, |
The transistor goes into cutoff |
88. A type of 4 arm capacitance bridge, in which the unkown capacitance is compared with the standard capacitance. This bridge is frequently employed to test electrolytic capacitors to which a TV polarizing voltage is applied during the measurement. |
Schering bridge |
89. In dc motors, when does severe arcing happens |
During starting |
90. In an OTA the transconductance is controlled by |
Bias current |
91. The 3 parts of a basic isolation amplifier are |
Input, Output and power |
92. The power dissipation of a class C amplifier is |
Very low |
93. Transient suppression minimizes the chance of |
Diode failure |
94. Generally, in dc motors |
The armature winding is supplied with current or the armature is placed inside the set of magnetic poles |
95. The multistage transistor amplifier arranged in a conventional series manner, the output voltage is forward coupled to the next amplifier |
Cascaded amplifier |
96. Typically an instrumentation amplifier has an external resistor used for |
Setting the voltage gain |
97. The T-MOSFET is a special type of |
E-MOSFET |
98. The wien bridge oscillator’s positive feedback circuit is |
Lead/lag circuit |
99. When the 2 inputs of a multiplier are connected together, the device operates a |
Squaring circuit |
100. In FET, the conduction path of the output is controlled by the electric field as it name implies, how does an electric field in an FET established |
When the charges present at the gate choose a reverse biased junction |
101. Why do you need a noise generator |
When evaluating noise characteristics of amplifier |
102. In the case of load regulation |
When the load changes, the output voltage is phase constant |
Post a Comment