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