diode applications

Question 1

Which diode(s) has (have) a zero level current and voltage drop in the ideal model?

A) Si
B) Ge
C) Both Si and Ge
D) Neither Si nor Ge

Answer 1

C) Both Si and Ge

Question 2

In a voltage regulator network with fixed RL and R, what element dictates the minimum level of source voltage?

A) VZ
B) IZ
C) IZM
D) None of the above

Answer 2

A) VZ

Question 3

A Zener diode is in a _______ impedance region in the forward bias while it has a _______ impedance region in the reverse bias.

A) very large, low
B) very large, very large
C) low, low
D) low, very large

Answer 3

D) low, very large

Question 4

The load line is defined by the _______ and a characteristic curve is defined by the _______.

A) quiescent point, device
B) device, network
C) network, device
D) None of the above

Answer 4

C) network, device

Question 5

The PIV rating of the diodes in a full-wave rectifier must be larger than _______ Vm.

A) 0.318
B) 0.636
C) 2
D) 1

Answer 5

D) 1

Question 6

Rectifiers are commonly used in battery chargers.

A) True
B) False

Answer 6

A) True

Question 7

The slope of the load line depends on the _______.

A) type of the diode used
B) characteristic curve
C) load resistor
D) source voltage

Answer 7

C) load resistor

Question 8

The combination of a short circuit in series with an open circuit always results in a(n) _______ circuit.

A) open
B) short
C) neither short nor open
D) unknown

Answer 8

A) open

Question 9

The source voltage must be _______ the voltage drop across the diode to conduct the diode.

A) larger than
B) smaller than
C) the same as
D) None of the above

Answer 9

A) larger than

Question 10

What is the peak inverse voltage across each diode in a voltage doubler?

A) Vm
B) 2 Vm
C) 0.5 Vm
D) 0.25 Vm

Answer 10

B) 2 Vm

Question 11

List the categories of clippers.

A) Series
B) Parallel
C) Series and parallel
D) None of the above

Answer 11

C) Series and parallel

Question 12

An open circuit can have any voltage across its terminals, but the current is always ________.

A) 5 A
B) 0 A
C) 1 A
D) ∞

Answer 12

B) 0 A

Question 13

A diode is in the “_____” state if the current established by the applied sources is such that its direction matches that of the arrow in the diode symbol, and VD ≥ 0.7 V for Si and VD ≥ 0.3 V for Ge.

A) off
B) on
C) neutral
D) quiescent

Answer 13

B) on

Question 14

The x-intercept of the load line with the characteristic curve is determined by the _______.

A) load resistor
B) diode
C) source voltage and the load resistor
D) source voltage

Answer 14

D) source voltage

Question 15

For the “off” state of a Zener diode, the voltage across the diode should be _______.

A) greater than VZ
B) zero
C) less than VZ but greater than zero
D) None of the above

Answer 15

C) less than VZ but greater than zero

Question 16

As the load resistor increases, the slope of the dc load line and the levels of diode current ______.

A) increase
B) decrease
C) remain unchanged
D) are unpredictable

Answer 16

B) decrease

Question 17

A germanium diode is approximated by _______ equivalent for voltages less than 0.3 V.

A) a short circuit
B) a series circuit
C) a parallel circuit
D) an open circuit

Answer 17

D) an open circuit

Question 18

The dc voltage level of a silicon diode is _______ its ideal model.

A) smaller than
B) larger than
C) the same as
D) None of the above

Answer 18

B) larger than

Question 19

The full-wave voltage doubler provides _______ filtering action than (as) the half-wave voltage doubler.

A) better
B) poorer
C) the same
D) None of the above

Answer 19

A) better

Question 20

For the ideal diode the transition between states will occur at the point on the characteristic curve when VD = _______ V and ID = _______ A.

A) 0.3, 0
B) 0, 0
C) 0.7, 0
D) 0.7, 0.3

Answer 20

B) 0, 0

Question 21

The quiescent point (Q-point) is defined by a(n) _______.

A) ac network
B) dc network
C) ac and dc network
D) None of the above

Answer 21

B) dc network

Question 22

Determine the total discharge time for the capacitor in a clamper having C = 0.01 µF and R = 500 kΩ.

A) 5 ms
B) 25 ms
C) 2.5 ms
D) 50 ms

Answer 22

B) 25 ms

Question 23

The absence of the Si or Ge and VD label on a diode denotes _______ notation.

A) approximate model
B) ideal model
C) exact model
D) None of the above

Answer 23

B) ideal model

Question 24

A short circuit has a _____ drop across its terminals, and the current is limited only by the surrounding network.

A) 5 V
B) 0 V
C) 1 V
D) ∞

Answer 24

B) 0 V

Question 25

Zener diodes are used in regulator networks to _______.

A) generate voltage
B) consume power
C) maintain a fixed voltage across the load resistor
D) protect the load

Answer 25

C) maintain a fixed voltage across the load resistor

Question 26

The ratio of the total swing of the output of a clamper to its input total swing is _______.

A) 1
B) 2
C) 0.5
D) 0

Answer 26

A) 1

Question 27

With the Zener diode in the “on” state, increasing IL will _____ IZ and _____IR.

A) decrease, increase
B) increase, decrease
C) decrease, keep the same level of
D) increase, keep the same level of

Answer 27

C) decrease, keep the same level of

Question 28

Once the Zener diode is in the “on” state, VZ is always _______ VL.

A) larger than
B) smaller than
C) the same as
D) None of the above

Answer 28

C) the same as