Deck 2: Diodes

Question 1

The ideal model of a pn-junction diode represents the device as a

A) switch.
B) switch in series with a battery.
C) switch in series with a battery and a resistor.

Answer 1

switch.

Question 2

The diode model is typically used in circuit calculations.

A) ideal
B) practical
C) complete

Answer 2

practical

Question 3

A zener diode has the following ratings: VZ = 9.1 V and IZT = 20 mA. The measured value of VZ changes by 30 mV when Izt = 2 mA. What is the value of ZZ for the device?

A) 1.5 Ω
B) 15 Ω
C) 30 Ω
D) 3.0 Ω

Answer 3

15 Ω

Question 4

The voltage across the resistor in Figure is

A) 6 V.
B) 5.3 V.
C) 0.7 V.
D) 0 V.

Question 5

The voltage across a resistor is calculated as being 4 V. The measured value of the voltage is 4.3 V. What is the percent of error between the two values?

A) 6.98%
B) 7.5%
C) 0.698%
D) 0.075%

Question 6

The diode model is typically used in the initial stages of troubleshooting.

A) ideal
B) practical
C) complete

Question 7

A zener diode is designed to operate in the region of its characteristic curve.

A) forward operating
B) reverse breakdown
C) zero bias

Question 8

A maximum rating on a spec sheet is a

A) quality.
B) limit.
C) average value.
D) ac characteristic.

Question 9

When substituting one diode for another, you must consider the

A) average forward current and bulk resistance ratings.
B) peak reverse voltage and diode capacitance ratings.
C) average forward current and peak reverse voltage ratings.
D) bulk resistance and diode capacitance ratings.

Question 10

The p-type material of a diode is called the

A) anode.
B) cathode.

Question 11

The voltage across the diode in Figure is

A) 5 V.
B) 4.3 V.
C) 0.7 V.
D) 0 V.

Question 12

The diode model is typically used in circuit development applications.

A) ideal
B) practical
C) complete

Question 13

Electron flow through a forward-biased pn junction is

A) from cathode to anode.
B) from anode to cathode.

Question 14

A pn-junction diode conducts when the arrow in the schematic symbol

A) points to the more negative diode potential.
B) points to the more positive diode potential.

Question 15

Conventional current through a forward-biased pn junction is

A) from cathode to anode.
B) from anode to cathode.

Question 16

The voltage across the resistor in Figure is

A) 5 V.
B) 4.3 V.
C) 0.7 V.
D) 0 V.

Question 17

The voltage across the diode in Figure is

A) 6 V.
B) 5.3 V.
C) 0.7 V.
D) 0 V.

Question 18

A calculated value is generally considered to be accurate enough when it is within

A) 20% of the measured value.
B) 15% of the measured value.
C) 10% of the actual value.
D) 5% of the actual value.
Figure 2-1

Question 19

The n-type material of a diode is called the

A) anode.
B) cathode.

Question 20

A silicon diode has a bulk resistance of 12 Ω and a forward current of 7 mA. The forward voltage drop across the diode is approximately

A) 700 mV.
B) 784 mV.
C) 84 mV.
D) 884 mV.

Question 21

A given LED has a maximum forward current rating of 30 mA. You should use IF = to calculate the value of the current-limiting resistor.

A) 30 mA
B) 24 mA
C) 36 mA
D) 20 mA
Chapter 2 Diodes Answer Key

Question 22

What is the value of IT for the circuit in Figure ?

A) 3 mA
B) 1 mA
C) 5 mA
D) 12 mA

Question 23

An LED is typically wired in series with a current-limiting resistor.

Question 24

The color of an LED is typically determined by the magnitude of the diode current.

Question 25

When tested with an ohmmeter, a diode should have forward resistance and reverse resistance.

A) low; high
B) high; low
C) high; high
D) low; low

Question 26

Which diode type can be best utilized as a panel indicator?

A) A pn-junction diode
B) A zener diode
C) A light-emitting diode LED)
D) None of the above.

Question 27

The stripe on the body of a pn-junction diode is used to identify the .

A) cathode
B) anode

Question 28

Which of the following steps should be taken when testing a diode with an ohmmeter?

A) The ohmmeter should be calibrated using the zero adjust when applicable).
B) The relative polarity of the meter leads should be checked.
C) The meter output current level for each resistance scale should be verified as being safe for the diode under test.
D) All of the above.

Question 29

The anode and cathode leads on an LED are usually identified by

A) their color.
B) their lengths.
C) a marking on the LED case.
D) their lengths and/or a marking on the LED case.

Question 30

Symbols A, B, and C represent the , respectively.

A) LED, zener diode, and pn-junction diode
B) zener diode, pn-junction diode, and LED
C) photo diode, zener diode, and LED
D) LED, pn-junction diode, and zener diode

Question 31

The driving circuit has a peak output of 6 V. What value of RS will protect the LED from excessive forward current?

A) 470 Ω
B) 560 Ω
C) 680 Ω
D) Any of the resistors listed will protect the LED.

Question 32

Which of the following is most likely to destroy a zener diode?

A) Exceeding VBR
B) Exceeding IZM