Electronics Engineering 1 - Part 1
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This includes basic electronics engineering topics.
- 1.It is a process when the reverse voltage applied to zener diode exceeds the selected reverse breakdown voltage that occurs in the depletion layer and the current through the diode increases to the maximum circuit value, which is usually limited by a series resistor.
- A.
Avalanche breakdown
- B.
Regulation
- C.
Stabilization
- D.
Reverse breakdown
- 2.The most basic passive components in electrical or electronic circuits are
- A.
Resistors
- B.
Capacitors
- C.
Inductors
- D.
Diodes
- E.
Batteries
- 3.Semiconductors ability to conduct electricity can be greatly improved by adding certain impurities to the crystalline structure thereby, producing more free electrons than holes or vice versa.
- A.
The statement is TRUE.
- B.
The statement is FALSE.
- C.
The statement is sometimes TRUE.
- D.
Not applicable
- 4.These atoms allow some of the electrons to bond with its neighbouring silicon atoms leaving one "free electron" to move about when an electrical voltage is applied and are also called "donors".
- A.
Pentavalent impurities
- B.
Crystals
- C.
Trivalent impurities
- D.
P-type semiconductor
- 5.These are negatively charged and there are a large number of holes with a small number of free electrons in relation to the number of holes.
- A.
Pentavalent impurities
- B.
Crystals
- C.
Trivalent impurities
- D.
N-type semiconductor
- 6.In a semiconductor crystal, the atoms are held together by
- A.
The interaction of valence electrons
- B.
Forces of attraction
- C.
Covalent bonds
- D.
Answers (A), (B), and (C)
- 7.When the N and P-type semiconductor materials are first brought together some of the free electrons move across the junction to fill up the holes in the P-type material producing _________________.
- A.
Free electrons
- B.
Positive ions
- C.
Negative ions
- D.
Pn junction
- 8.A widely used application of the power diode is in the conversion of alternating voltages (AC) to direct voltages (DC), called _____________.
- A.
Diffusion
- B.
Rectification
- C.
Amplification
- D.
Modification
- 9.In a half-wave rectifier circuit, during each "positive" half cycle of the AC sine wave, the diode is ______________.
- A.
Reverse bias
- B.
Forward bias
- C.
Unidirectional
- D.
Ideal
- 10.One of the ways of reducing the ripple or voltage variations on a direct DC voltage is by _______________.
- A.
Connecting capacitors across the load resistance
- B.
Connecting resistor across the diode
- C.
Connecting a transformer to the circuit
- D.
Connect a diode across the load resistance
- 11.
- A.
It has a smaller AC ripple value for a given load
- B.
It has a smaller reservoir or smoothing capacitor than
- C.
It produces fundamental frequency of the ripple voltage twice that of the AC supply frequency
- D.
All of the above
- E.
(A) and (B)
- 12.If the load resistance of a capacitor-filtered full-wave rectifier is reduced, the ripple voltage _________.
- A.
Decreases
- B.
Increases
- C.
Is not affected
- D.
Has a different frequency
- 13.Valence electrons are
- A.
In the closest orbit to the nucleus
- B.
In the most distant orbit from the nucleus
- C.
In various orbits around the nucleus
- D.
Not associated with a particular atom
- 14.A positive ion is formed when ________.
- A.
there are more holes than electrons in the outer orbit
- B.
Two atoms bond together
- C.
An atom gains an extra valence electron
- D.
A valence electron breaks away from the atom
- 15.A technique where no external voltage potential is applied to the PN-junction.
- A.
Reversed bias
- B.
Forward bias
- C.
Zero bias
- D.
Avalance breakdown
- 16.The voltage potential is connected negative to the P-type material and positive to the N-type material across the diode which has the effect of increasing the PN-junction width.
- A.
Zero bias
- B.
Reverse bias
- C.
Forward bias
- D.
Depletion layer
- 17.Semiconductors contain two types of mobile charge carriers.
- A.
TRUE
- B.
FALSE
- C.
The statement is TRUE depending on the type of material.
- D.
The statement is FALSE when fully charged with electrons.
- 18.A natural potential barrier is developed across a PN-junction which is about 0.7v for Silicon diodes and about 0.3v for Germanium diodes when __________.
- A.
Zero bias
- B.
Forward bias
- C.
Reverse bias
- D.
Connected with capacitor
- 19.Which of the following is not included in the group?
- A.
Boron
- B.
Antimony
- C.
Indium
- D.
Gallium
- E.
Aluminum
- 20.Which of the following is not included in the group?
- A.
Phosphorus
- B.
Arsenic
- C.
Antimony
- D.
Aluminum
- E.
Bismuth
- 21.The energy band in which free electrons exist is the _________.
- A.
First band
- B.
Second band
- C.
Conduction band
- D.
Valence band
- 22.Each atom in a silicon crystal has _________.
- A.
Four valence electrons
- B.
Four conduction electrons
- C.
Eight valence electrons, four of its own and four shared
- D.
No valence electrons because all are shared with other atoms
- 23.The current in a semiconductor is produced by _________.
- A.
Electron only
- B.
Holes only
- C.
Negative ions
- D.
Both electrons and holes
- 24.The purpose of pentavalent impurity is to ________.
- A.
Reduce the conductivity of silicon
- B.
Increase the number of holes
- C.
Increase the number of free electrons
- D.
Create minority carriers
- 25.The term bias means ___________.
- A.
The ratio of majority carriers to minority carriers
- B.
The amount of current across the diode
- C.
A dc voltage is applied to control the operation of a device
- D.
Neither (A), (B), nor (C)
- 26.To forward-bias a diode, _____________________.
- A.
An external voltage is applied that is positive at the anode and negative at the cathode
- B.
An external voltage is applied that is negative at the anode and positive at the cathode
- C.
An external voltage is applied that is positive at the p region and negative at the n region
- D.
Answers (A) and (C)
- E.
Answers (B) and (C)
- 27.Although current is blocked in reverse bias, ______________.
- A.
There is some current due to majority carriers
- B.
There is a very small current due to minority carriers
- C.
There is an avalanche current
- D.
There is a very small current due to battery
- E.
There is some current due to free electrons
- 28.When a voltmeter is placed across a forward-biased diode, it will read a voltage approximately equal to ______________.
- A.
The bias battery voltage
- B.
0 V
- C.
The diode barrier potential
- D.
The total circuit voltage
- 29.A silicon diode is in series with a 1.0kW resistor and a 5 V battery. If the anode is connected to the positve battery terminal, the cathode voltage with respect to the negative battery terminal is ___________.
- A.
0.7V
- B.
0.3V
- C.
5.3V
- D.
4.3V
- 30.The postive lead of an ohmmeter is connected to the anode of a diode and the negative lead is connected to the cathode. The diode is _____________.
- A.
Reversed-bias
- B.
Open
- C.
Forward-bias
- D.
Faulty
- E.
Answers (B) and (D)
- 31.If one of the diodes in a bridge full-wave rectifier opens, the output is _______.
- A.
0V
- B.
One-fourth the amplitude of the input voltage
- C.
A half-wave rectified voltage
- D.
A 120 Hz voltage
- 32.A 10V peak-to-peak sinusoidal voltage is applied across a silicon diode and series resistor. The maximum voltage across the diode is ________.
- A.
9.3V
- B.
10V
- C.
5
- D.
4.3V
- E.
0.7V
- 33.What is the input rms voltage, when the average voltage value of a half-wave rectifier is 35V?
- A.
110V
- B.
49.5V
- C.
78V
- D.
220V
- 34.What is the secondary rms voltage of a bridge rectifier when the peak-to-peak voltage is 40V (use second approximation)?
- A.
19.8V
- B.
27.29V
- C.
29.27V
- D.
13.15V
- E.
15.13V
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