Deck 2: Diodes and Applications

Question 1

Figure 4
Refer to Figure 4. Assume the diode is a practical diode. If the diode is reversed, the current in the diode will be

A)0 mA
B)4.7 mA
C)5.7 mA
D)0.2 mA

Answer 1

A

Question 2

To convert the rms value of a sine wave to a peak value,

A)multiply the rms value by 0.637
B)divide the rms value by 0.707
C)multiply the rms value by 0.707
D)divide the rms value by 0.637

Answer 2

B

Question 3

A voltage regulator compensates for changes in

A)temperature effects
B)load conditions
C)input voltage changes
D)all of the above

Answer 3

D

Question 4

Figure 8
The maximum output voltage for the circuit in Figure 8 is approximately (Assume an ideal diode.)

A)Vp(in)
B)2Vp(in)
C)-Vp(in)
D)0 V

Question 5

Figure 5
Refer to the circuit in Figure 5. The rms primary current is approximately

A)5.0 mA
B)500 mA
C)50 mA
D)0.5 mA

Question 6

Reverse current in a diode increases if

A)voltage increases
B)temperature increases
C)both A and B
D)none of the above

Question 7

The ripple frequency of a bridge rectifier is

A)equal to the input frequency
B)double the input frequency
C)four times the input frequency
D)half the input frequency

Question 8

Figure 2
Refer to Figure 2. The circuit that will produce a positive output is

A)(a)
B)(b)
C)(c)
D)(d)

Question 9

The ideal dc output voltage of a capacitor- input filter equals the

A)one- half of the peak of the rectified voltage
B)average value of the rectified voltage
C)peak value of the rectified voltage
D)rms value of the rectified voltage

Question 10

Another name for a diode limiter circuit is

A)clipper
B)clamper
C)dc restorer
D)rectifier

Question 11

A capacitor filtered half- wave rectifier has a ripple frequency that is

A)half that of the input frequency
B)twice that of the input frequency
C)the same as the input frequency
D)1.5 times the input frequency

Question 12

Figure 1
The circuit in Figure 1 is a

A)clamping circuit
B)bridge rectifier
C)center- tapped full- wave rectifier
D)half- wave rectifier

Question 13

Figure 5
Refer to the circuit in Figure 5. The purpose of Rsurge is to

A)prevent load current from exceeding safe limits
B)prevent overheating the transformer
C)prevent an inrush of current that could damage diodes
D)all of the above

Question 14

Assume an ideal diode has a series 10 k▲ resistor and is reverse- biased with a 5.0 V source. The current in the diode is

A)0 mA
B)0.5 mA
C)2.0 mA
D)1.0 mA

Question 15

The VRRM specification on a manufacturer's data sheet is the same as the

A)forward voltage at maximum power
B)reverse breakdown voltage
C)forward voltage with 1 A of current
D)PIV

Question 16

In a full wave bridge rectifier with a capacitor filter, assume a diode has opened. You expect to see

A)an increase in the ripple frequency
B)an increase in the ripple voltage
C)both A and B
D)none of the above

Question 17

Figure 8
The circuit in Figure 8 is a

A)negative clipping circuit
B)negative clamping circuit
C)positive clipping circuit
D)positive clamping circuit

Question 18

The forward resistance of a diode is

A)constant
B)extremely high at all points
C)lower above the knee
D)lower below the knee

Question 19

C:\User Figure 7
For questions 34, 35, and 36, assume ideal diodes
Which circuit in Figure 6 will produce the waveform in Figure 7(c)?

A)(a)
B)(b)
C)(c)
D)(d)

Question 20

A capacitor filtered full- wave rectifier has a ripple frequency that is

A)1.5 times the input frequency
B)twice that of the input frequency
C)the same as the input frequency
D)half that of the input frequency

Question 21

The anode of a diode is usually marked by a band, a tab, or some other feature.

Question 22

Figure 1
For the circuit in Figure 1, assume ideal diodes. The peak inverse voltage is approximately

A)42 V
B)21 V
C)36 V
D)0 V

Question 23

Figure 1
For the circuit in Figure 1, assume ideal diodes. The average voltage you should observe across RL is

A)13.5 V
B)19.2 V
C)9.6 V
D)27.0 V

Question 24

To forward bias a diode, the n- region is connected to the positive side of a voltage source.

Question 25

Figure 3
For the circuit in Figure 3, assume practical diodes. The peak output voltage across the load is

A)16.3 V
B)17.7 V
C)7.8 V
D)9.2 V

Question 26

Figure 2
Refer to Figure 2. The circuit that will produce a negative output is

A)(a)
B)(b)
C)(c)
D)(d)

Question 27

Figure 3
For the circuit in Figure 3, assume a diode opens. As a result, the peak output voltage will be

A)larger
B)zero
C)approximately the same
D)halved

Question 28

An ideal diode is considered to have a small forward voltage drop across the junction.

Question 29

When a diode is forward- biased, the depletion region narrows.

Question 30

A silicon diode measures a very high value of resistance in one direction and very low resistance in the other. This indicates the diode is probably

A)good
B)open
C)shorted

Question 31

The component(s)immediately preceding the voltage regulation stage in a power supply is

A)a filter capacitor
B)the fuse
C)the transformer
D)the diodes

Question 32

Figure 9
The circuit in Figure 9 is a

A)clipping circuit
B)voltage doubler
C)voltage tripler
D)limiter circuit

Question 33

Figure 4
Refer to Figure 4. Assume the diode is a practical diode. The current in the diode will be

A)4.7 mA
B)5.7 mA
C)0 mA
D)0.2 mA

Question 34

C:\User Figure 7
For questions 34, 35, and 36, assume ideal diodes
Which circuit in Figure 6 will produce the waveform in Figure 7(a)?

A)(a)
B)(b)
C)(c)
D)(d)

Question 35

When a diode is reverse- biased, the current is normally extremely small.

Question 36

Assume an ideal diode has a series 10 k▲ resistor and is forward- biased with a 20 V source. The current in the diode is

A)2.0 mA
B)0 mA
C)1.0 mA
D)0.5 mA

Question 37

For a forward- biased diode, as temperature increases, forward current also increases.

Question 38

Figure 5
Refer to the circuit in Figure 5. The current in the load resistor is approximately

A)10 mA
B)5 mA
C)15 mA
D)2.5 mA

Question 39

Dynamic resistance is the same as linear resistance.

Question 40

C:\User Figure 7
For questions 34, 35, and 36, assume ideal diodes
Which circuit in Figure 6 will produce the waveform in Figure 7(b)?

A)(a)
B)(b)
C)(c)
D)(d)