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.

True

False

 

Question 2  

The bridge rectifier is similar to a full-wave rectifier because it produces a full-wave output voltage. 

True

False

 

Question 3  

A semiconductor is an element with electrical properties between those of a conductor and those of an insulator.

True

False

 

 

Question 4                 

The dc beta is defined as the dc collector current divided by the dc emitter current.

True

False

 

 

Question 5  

An ideal diode acts like a switch that closes when forward-biased and opens when reverse-biased.

True

False

 

 

Question 6  

With a half-wave rectifier, the output frequency equals the input frequency.

True

False

 

 

Select Correct Answers from the Following

 

Question 7  

A pure semiconductor is also referred to as:

    a clean room device
    intrinsic
    extrinsic
    Transistor

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
    intrinsic

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
    exponential

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:

    shorted
    leaky
    open
    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
    rectified.

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?

    collector
    emitter
    base
    beta

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:

IB

IE

VCE

VE

VB

20 points