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ET 212 Final Examination Answers – Grantham
Select True / False from the following :
Question 1  
The two basic kinds of transistor circuits are amplifying and switching.
Question 2  
The bridge rectifier is similar to a full-wave rectifier because it produces a full-wave output voltage.
Question 3  
A semiconductor is an element with electrical properties between those of a conductor and those of an insulator.
Question 4                 
The dc beta is defined as the dc collector current divided by the dc emitter current.
Question 5  
An ideal diode acts like a switch that closes when forward-biased and opens when reverse-biased.
Question 6  
With a half-wave rectifier, the output frequency equals the input frequency.
Select Correct Answers from the Following
Question 7  
A pure semiconductor is also referred to as:
a clean room device
4 points
Question 8  
Silicon that has been doped with a trivalent impurity is called a:
N-type semiconductor
P-type semiconductor
P-N junction
covalent bond
4 points
Question 9
In a silicon atom, what is the distance between the valence band and the conduction band called?
energy gap
depletion layer
P-N junction
4 points
Question 10
 A diode is a nonlinear device because the graph of its current versus voltage is:
a straight line
not a straight line
inversely proportional to the resistance
4 points
Question 11
 Ideally, a diode acts like a perfect conductor when forward-biased and:
like a perfect conductor when reverse-biased
like a perfect semiconductor when reverse-biased
like a perfect insulator when reverse-biased
like a perfect diode when reverse-biased
4 points
Question 12
 A diode that exhibits high resistance in both directions when measured with an ohmmeter is:
a properly operating diode
4 points
Question 13
 The knee voltage of a germanium diode is approximately ________.
0.7 V
0.3 V
1.7 V
1.3 V
4 points
Question 14
 Much of the information on a manufacturer’s data sheet is:
necessary to understand diode circuits
necessary to troubleshoot diode circuits
obscure and of use only to circuit designers
necessary only to electronics technicians
4 points
Question 15
The output frequency of a half-wave rectifier is:
twice the input frequency
half the input frequency
equal to the input frequency
four times the input frequency
4 points
Question 16
 A step-up transformer will produce a secondary voltage that is:
smaller than the primary
equal to the primary
larger than the primary
4 points
Question 17
 What is the name of the circuit shown in the Figure 1 below?
Figure 1
half-wave rectifier
full-wave rectifier
bridge rectifier
voltage doubler
4 points
Question 18
 Which region of the transistor is physically the largest?
4 points
Question 19
 Kirchhoff’s current law describes transistor currents as follows:
emitter current equals the sum of collector and base currents.
collector current equals the sum of base and emitter currents.
base current equals the sum of collector and emitter currents.
emitter current equals collector current minus the base current.
4 points
Question 20
Refer to Figure 2 below, what is the possible problem if VB is equal to 0 V and VC is equal to 15 V?
Figure 2
transistor is shorted
RB is open
VCC is 0 V
transistor is blown open
4 points
Question 21
 Refer to Figure 2, what is the possible problem if VB is equal to 15 V and VC is equal to 15 V?
Figure 2
transistor is blown open
VBB is 0 V
transistor is shorted
VCC is 0 V
4 points
Question 22
 Using the load line shown in Figure 3, what is the transistor’s collector current if biased at the point labelled Q?
Figure 3
1.5 mA
3 mA
4.5 mA
7 mA
4 points
Question 23
 In the circuit shown in the Figure 4 below, calculate the saturation current?
Figure 4
4 points
Question 24
 In the Common Collector (CC) circuit of Figure 5 below consider β = 49 and VBE = 0.7 V.
Figure 5
Find the following:
20 points