Deck 3: Diode Theory Key

Question 1

Some data sheets list reverse breakdown voltage as PIV,PRV,or BV.

Answer 1

True

Question 2

Measuring high resistance in both directions on a diode indicates an open diode.

Answer 2

False

Question 3

In a diode,after the barrier potential is overcome,all that impedes the current is the

A) ohmic resistance of the p and n regions.
B) bulk resistance.
C) dynamic resistance of the p region.
D) depletion resistance.

Answer 3

A

Question 4

The p side of a diode is referred to as the

A) positive terminal.
B) triode.
C) anode.
D) cathode.

Question 5

The dc resistance of a diode is the same as the bulk resistance.

Question 6

You can quickly check the condition of a diode with an ohmmeter on a high resistance range.

Question 7

The load line is a tool used to and the exact value of a diode current and voltage.

Question 8

An ideal diode acts like a switch that closes when forward-biased and opens when reverse-biased.

Question 9

The maximum forward current is one of the maximum ratings given on a data sheet.

Question 10

A diode is a nonlinear device because thegraph of its current versus voltage is

A) a straight line.
B) not a straight line.
C) inversely proportional to the resistance.
D) exponential.

Question 11

The sum of the ohmic resistances of a diode is called the ideal resistance.

Question 12

The sum of the ohmic resistances is called the

A) depletion layer.
B) ohmmeter.
C) impedance.
D) bulk resistance.

Question 13

The ratio of total voltage to total diode current is the dc resistance of the diode.

Question 14

An ordinary resistor is a linear device because the graph of its current versus voltage is a straight line.

Question 15

If the current in a diode is too large

A) the load resistor will short.
B) excessive heat may destroy the diode.
C) the diode becomes an ampli er.
D) bulk resistance becomes smaller.

Question 16

The letter Q is an abbreviation for quiescent,which means at rest.

Question 17

Surface mount diodes are large and ine cient.

Question 18

Manufacturer's data sheets generally list the value of bulk resistance.

Question 19

A diode that measures extremely low resistance in both directions is called a leaky diode.

Question 20

Much of the information on a manufacturer's datasheet is obscure and of use only to circuit designers.

Question 21

The knee voltage of a germanium diode is approximately ________.

A) 0.7 V
B) 0.3 V
C) 1.7 V
D) 1.3 V

Question 22

In the forward region,the voltage at which thecurrent starts to increase rapidly is called

A) the depletion voltage of the diode.
B) the saturation current of the diode.
C) the cuto voltage of the diode.
D) the knee voltage of the diode.

Question 23

How is the power dissipation of a diode calculated?

A) diode current times diode resistance
B) diode voltage divided by diode current
C) diode voltage times diode current
D) diode current divided by diode voltage

Question 24

A diode that exhibits high resistance in bothdirections when measured with an ohmmeter is

A) shorted.
B) leaky.
C) open.
D) a properly operating diode.

Question 25

All silicon diodes have a knee voltage of approximately ________.

A) 0.7 V
B) 0.4 V
C) 1.4 V
D) 1.7 V

Question 26

The two most popular basic styles of surface-mount packages are surface mount and

A) small outline transistor.
B) large outline transistor.
C) surface outline diode.
D) surface outline transistor.

Question 27

With regard to reverse breakdown voltage,conservative design engineers generally use a safety factor of

A) 2
B) 5
C) 10
D) 100

Question 28

In diode third approximation calculations,bulk resistance can be ignored if

A) silicon diodes are used.
B) it is less than 1 Ω.
C) it is greater than 1Ω.
D) it equals diode voltage divided by diode current.

Question 29

When graphing the diode,the greater the slope of the diode curve

A) the smaller the bulk resistance.
B) the greater the bulk resistance.
C) the smaller the forward current.
D) the lower the power dissipated.

Question 30

What is the condition that causes a diode togo into avalanche when a huge number of carriers suddenly appear in the depletion layer?

A) forward voltage drop
B) maximum power dissipation
C) reverse breakdown voltage
D) maximum forward current

Question 31

What is the data sheet speci cation that stsli the reverse current at the maximum reverse dc rated voltage?

A) reverse breakdown
B) maximum forward current
C) maximum reverse current
D) forward breakdown

Question 32

Which of the following is not an advantage of using surface-mount diodes?

A) small
B) e cient
C) inexpensive
D) easy to test

Question 33

The dc resistance of a diode equals

A) the bulk resistance.
B) the bulk resistance plus the effect of the barrier potential.
C) the bulk resistance minus the e ect of the barrier potential.
D) zero.

Question 34

The point of intersection,whichis called the Q point,represents

A) the intersection of the diode curve and the load line.
B) the intersection of cuto and the diode voltage.
C) the intersection of saturation and diode current.
D) the intersection of cuto and diode current.

Question 35

In the third approximation of a diode,

A) the depletion layer is ignored.
B) the ohmic resistance is ignored.
C) the bulk resistance is ignored if greater than 1Ω.
D) the bulk resistance is included.

Question 36

The second approximation of a silicon diode is basically

A) the diode appears as a switch in series with a barrier potential of 0.7 V.
B) the diode appears as a switch in parallel with a barrier potential of 0.7 V.
C) the diode appears as a barrier potential of 0.4 V.
D) the diode appears as a short circuit.

Question 37

Ideally,a diode acts like a perfect conductor when forward-biased and

A) like a perfect conductor when reverse-biased.
B) like a perfect semiconductor when reverse-biased.
C) like a perfect insulator when reverse-biased.
D) like a perfect diode when reverse-biased.

Question 38

When a more accurate value for diode load current and load voltage is required,

A) the rst approximation is used.
B) the second approximation is used.
C) Ohm's Law is used.
D) Thevenin's Theorem is used.

Question 39

Most electronic troubleshooters begin by measuring

A) voltages out of the power supply.
B) resistances of the diodes.
C) power of the diodes.
D) current out of the power supply.

Question 40

A diode can be e ectively checked by using

A) an oscilloscope.
B) a frequency counter.
C) a spectrum analyzer.
D) an ohmmeter.

Question 41

What is the manufacturer's data sheet entry that lists the maximum current a diode recti er can handle in the forward direction?

A) reverse breakdown
B) maximum power dissipation
C) maximum forward current
D) maximum reverse current

Question 42

When an accurate analysis of a diode circuit is required,

A) the value of the bulk resistance of the diode is necessary.
B) the value of maximum power dissipation of the diode is necessary.
C) the value of the depletion layer resistance of the diode is necessary.
D) the value of maximum reverse current of the diode is necessary.

Question 43

The ideal diode approximation is su cient

A) for most troubleshooting situations.
B) to determine very accurate values for load current and voltage.
C) for circuit design.
D) for analyzing transistor circuits.

Question 44

The ratio of total diode voltage to total diode current is the

A) bulk resistance.
B) dc resistance.
C) reactance.
D) impedance.

Question 45

When a diode burns out,it becomes a short circuit.

Question 46

Much of the information on a manufacturer's data sheet is

A) necessary to understand diode circuits.
B) necessary to troubleshoot diode circuits.
C) obscure and of use only to circuit designers.
D) necessary only to electronics technicians.

Question 47

An ideal diode acts like a switch that closes when

A) the bias voltage is zero.
B) reversed-biased.
C) forward-biased.
D) taken out of the circuit.

Question 48

As with many tiny surface mount devices,thedetermination of the PIN is obtained from

A) clues on the circuit board and schematic diagram.
B) reading the numbers on the device's underside.
C) reading the color code on the device's underside.
D) reading the label stamped on the top of the device.

Question 49

When graphing diode characteristics,a tool used to nd the exact value of diode current and voltage is the

A) ohmmeter.
B) oscilloscope.
C) load line.
D) third approximation.

Question 50

When testing a diode with an ohmmeter,a proper operating diode should

A) exhibit a high ratio of reverse to forward resistance.
B) exhibit a low ratio of reverse to forward resistance.
C) exhibit high resistance in both directions.
D) exhibit low resistance in both directions.