Deck 5: Special Applications Diodes

Question 1

When forward biased, the PIN diode acts as a

A) current-controlled resistance.
B) current-controlled capacitance.
C) voltage-controlled resistance.
D) voltage-controlled capacitance.

Answer 1

current-controlled resistance.

Question 2

The capacitance of a varactor varies

A) inversely with the width of its depletion layer.
B) directly with the width of its depletion layer.

Answer 2

inversely with the width of its depletion layer.

Question 3

A tuned amplifier contains a 2.2 mH inductor in its tank circuit, along with a varactor with the following ratings: Ct = 80 pF when Vr = 3 Vdc and CR = 3 for V = 3 Vdc to 6 Vdc. What is the resonant frequency of the circuit when VR = 3 Vdc?

A) 904.3 GHz
B) 758.7 kHz
C) 379.4 kHz
D) 189.9 MHz

Answer 3

379.4 kHz

Question 4

A tuned amplifier has a 2.2 mH inductor and a varactor in its tank. The varactor has the ratings Ct = 72 pf when Vr = 3 Vdc and a Cr = 2.7 for V = 3 Vdc to 6 Vdc. What is the resonant frequency of the circuit described when VR = 6 Vdc?

A) 599.8 kHz
B) 479.9 kHz
C) 657 kHz
D) 1.20 MHz

Question 5

The clamping voltage Vc) rating of a transient suppressor indicates

A) the maximum voltage across the device at a given value of reverse surge current.
B) the maximum reverse voltage that will not drive the component into its zener operating region.

Question 6

Which of the following are characteristics of an effective surge protection circuit?

A) High power dissipation capability and rapid turn-on time
B) High power dissipation capability and slow turn-on time
C) High voltage capability and rapid turn-on time
D) High voltage capability and slow turn-on time

Question 7

The maximum reverse standoff voltage VRWM) rating of a transient suppressor indicates

A) the voltage across the device while in its zener operating region.
B) the maximum reverse voltage that will not drive the component into its zener operating region.

Question 8

A series current regulator is used to

A) provide a constant input current to a load over a wide range of input voltages.
B) provide a load with an input current that equals the difference between the source current and the regulator current.

Question 9

When reverse biased, the capacitance of a PIN diode can be varied like that of the varactor.

Question 10

The PIN diode actually contains pn junctions).

A) zero
B) one
C) two
D) three

Question 11

Forward voltage and current are directly proportional for a tunnel diode that is operated between its peak voltage VP ) and its valley voltage VV ).

Question 12

Schottky diodes have extremely low

A) VF, VRRM, and junction capacitance ratings.
B) IF, VRRM, and junction capacitance ratings.
C) VF, VK, and junction capacitance ratings.
D) fmax, VRRM, and VF ratings.

Question 13

The tunnel diode is a

A) lightly doped diode that is used in high-frequency communications applications.
B) lightly doped diode that is used in low-frequency communications applications.
C) heavily doped diode that is used in high-frequency communications applications.
D) heavily doped diode that is used in low-frequency communications applications.

Question 14

Constant-current diodes are also known as

A) current-restricting diodes.
B) current suppressors.
C) current regulator diodes.
D) All of the above.

Question 15

The tunnel diode region of operation between VP and VV is called the

A) constant resistance region.
B) constant current region.
C) negative resistance region.
D) negative current region.

Question 16

Constant-current diodes have

A) extremely low internal impedance values.
B) extremely high breakdown current ratings.
C) extremely high internal impedance values.
D) extremely low breakdown voltage ratings.

Question 17

A varactor with a high capacitance ratio CR) rating would be well suited for use in

A) a fine-tuning circuit.
B) a course-tuning circuit.
C) a crystal-controlled oscillator.
D) any of the circuits listed here.

Question 18

Back-to-back suppressors contain two components that are connected

A) anode-to-cathode.
B) anode-to-anode.
C) cathode-to-cathode.
D) either anode-to-anode or cathode-to-cathode.

Question 19

The varactor can be used as a

A) current-controlled capacitance when forward biased.
B) voltage-controlled capacitance when forward biased.
C) current-controlled capacitance when reverse biased.
D) voltage-controlled capacitance when reverse biased.

Question 20

The tunnel diode can be used as the active device in a

A) constant resistance amplifier.
B) negative resistance oscillator.
C) negative current rectifier.
D) negative resistance linear amplifier.

Question 21

This is the schematic symbol of a .

A) back to back suppressor
B) constant current diode
C) tunnel diode
D) Schottky diode

Question 22

The is sometimes referred to as a barrier diode, hot-carrier diode, or surface-barrier diode.

A) Tunnel diode
B) PIN diode
C) Step recovery diode
D) Schottky diode

Question 23

A tunnel diode has the following values: IP = 10 mA at VP = 250 mV and IV = 200 μA at VV = 480 mV
Calculate the dynamic resistance of the component.

A) -2.4 kΩ to -25 Ω
B) -23.5 Ω
C) +23.5 Ω
D) 25 Ω to 2.4 kΩ

Question 24

The doping level of a step-recovery diode

A) is extremely high.
B) is extremely low.
C) decreases as the distance from the junction increases.
D) increases as the distance from the junction increases.

Question 25

diodes are used in the manufacture of integrated circuit chips to decrease the propagation delay time of the internal circuits.

A) Constant current
B) Step recovery
C) Schottky
D) Tunnel

Question 26

Figure shows the schematic symbol for a

A) back to back suppressor.
B) constant current diode.
C) tunnel diode.
D) Schottky diode.

Question 27

Figure shows the schematic symbol for a

A) back to back suppressor.
B) constant current diode.
C) tunnel diode.
D) Schottky diode.

Question 28

Figure shows the schematic symbol for a

A) back to back suppressor.
B) constant current diode.
C) tunnel diode.
D) Schottky diode.

Question 29

The step-recovery diode is a/an

A) high-current diode.
B) high-voltage diode.
C) high-power diode.
D) ultra-fast diode.

Question 30

An engineer is designing a television tuner circuit. Which diode would you expect to see in the design?

A) A constant-current diode.
B) A tunnel diode.
C) A varactor diode.
D) A PIN diode.
Chapter 5 Special Applications Diodes Answer Key