Question 1

UJTs are used almost exclusively as

Accepted Answer

A)  breakover devices. 
B)  amplifiers. 
C)  thyristor triggering devices. 
D)  tuned oscillators. 
A)  breakover devices. 
B)  amplifiers. 
C)  thyristor triggering devices. 
D)  tuned oscillators. C

Question 2

A photodiode has a rating of s = 1200 nm. What is the optimum operating frequency for the device?

Accepted Answer

A)  250 THz 
B)  400 THz 
C)  250 × 1021 Hz 
D)  120 THz 
A)  250 THz 
B)  400 THz 
C)  250 × 1021 Hz 
D)  120 THz A

Question 3

The silicon unilateral switch SUS) is forced into forward conduction when VAK exceeds the rating of the device.

Accepted Answer

A)  forward conducting voltage 
B)  forward breakover voltage 
C)  forward trigger voltage 
D)  forward breakdown voltage 
A)  forward conducting voltage 
B)  forward breakover voltage 
C)  forward trigger voltage 
D)  forward breakdown voltage B

Question 4

The forward operating curve of the SCR is identical to that for the SUS.

Accepted Answer

A) True 
 B)False

Question 5

An SCR has a circuit fusing rating of 28 A2s. Will the device be destroyed if it is subjected to a 25 A surge that lasts for 50 ms?

Accepted Answer

A)  Yes 
B)  No 
A)  Yes 
B)  No

Question 6

The solid-state relay contains an internal

Accepted Answer

A)  optocoupler. 
B)  optointerrupter. 
C)  optoviewer. 
D)  optodivider. 
A)  optocoupler. 
B)  optointerrupter. 
C)  optoviewer. 
D)  optodivider.

Question 7

An SCR has a circuit fusing rating of 36 A2s. How long can the device withstand a 120 A surge?

Accepted Answer

A)  360 ms 
B)  90 ms 
C)  129.6 ms 
D)  2.5 ms 
A)  360 ms 
B)  90 ms 
C)  129.6 ms 
D)  2.5 ms

Question 8

Photodiodes are normally biased.

Accepted Answer

A)  forward 
B)  reverse 
C)  negatively 
D)  positively 
A)  forward 
B)  reverse 
C)  negatively 
D)  positively

Question 9

False triggering can be prevented by a

Accepted Answer

A)  damping network. 
B)  snubber network. 
C)  feedback network. 
D)  attenuating network. 
A)  damping network. 
B)  snubber network. 
C)  feedback network. 
D)  attenuating network.

Question 10

An object that blocks light is referred to as being

Accepted Answer

A)  transparent. 
B)  translucent. 
C)  opaque. 
D)  solid. 
A)  transparent. 
B)  translucent. 
C)  opaque. 
D)  solid.

Question 11

The speed of light c) is .

Accepted Answer

A)  300 m/s 
B)  3 × 10-18 cm/s 
C)  3 × 10-17 nm/s 
D)  186 m/s 
A)  300 m/s 
B)  3 × 10-18 cm/s 
C)  3 × 10-17 nm/s 
D)  186 m/s

Question 12

Light current through a photodiode is generally less than dark current.

Accepted Answer

A) True 
 B)False

Question 13

The amount of light per unit area that is received by a photodetector is called

Accepted Answer

A)  light intensity. 
B)  spectral wavelength. 
C)  light amplitude. 
D)  the light-area product. 
A)  light intensity. 
B)  spectral wavelength. 
C)  light amplitude. 
D)  the light-area product.

Question 14

Once an SUS is forced into forward conduction, it continues to conduct until IF drops below the rating of the device.

Accepted Answer

A)  minimum forward current 
B)  forward breakover current 
C)  holding current 
D)  dropout current 
A)  minimum forward current 
B)  forward breakover current 
C)  holding current 
D)  dropout current

Question 15

A PUT has a value of VGK = +8 V. What value of VAK is needed to trigger the device into conduction?

Accepted Answer

A)  -8 V 
B)  +16 V 
C)  +8 V 
D)  Cannot be determined from the information given. 
A)  -8 V 
B)  +16 V 
C)  +8 V 
D)  Cannot be determined from the information given.

Question 16

The primary difference between the diac and the SUS is the fact that

Accepted Answer

A)  the diac has a higher maximum power dissipation rating. 
B)  the SUS is capable of conducting in only one direction. 
C)  the diac is no longer used in any practical applications. 
D)  the SUS requires the use of a snubber. 
A)  the diac has a higher maximum power dissipation rating. 
B)  the SUS is capable of conducting in only one direction. 
C)  the diac is no longer used in any practical applications. 
D)  the SUS requires the use of a snubber.

Question 17

What are the two methods that are commonly used to return an SUS to its nonconducting state?

Accepted Answer

A)  Anode current interruption and forced commutation 
B)  Current holding and forced commutation 
C)  Anode current interruption and current holding 
D)  Forced commutation and current dropout 
A)  Anode current interruption and forced commutation 
B)  Current holding and forced commutation 
C)  Anode current interruption and current holding 
D)  Forced commutation and current dropout

Question 18

What is the wavelength of a 200 THz signal?

Accepted Answer

A)  50 pm 
B)  6.7 × 10-5 nm 
C)  1500 nm 
D)  60 nm 
A)  50 pm 
B)  6.7 × 10-5 nm 
C)  1500 nm 
D)  60 nm

Question 19

A photo-detector has a sensitivity rating of 3 μA/mW/cm2. This means that

Accepted Answer

A)  the forward current through the device will increase by 3 μA for every 1 mW/cm2 increase in light intensity. 
B)  the reverse current through the device will increase by 3 μA for every 1 mW/cm2 increase in light intensity. 
C)  the forward current through the device will increase by 3 μA for every 1 mW/cm2 decrease in light intensity. 
D)  the reverse current through the device will increase by 3 μA for every 1 mW/cm2 decrease in light intensity. 
A)  the forward current through the device will increase by 3 μA for every 1 mW/cm2 increase in light intensity. 
B)  the reverse current through the device will increase by 3 μA for every 1 mW/cm2 increase in light intensity. 
C)  the forward current through the device will increase by 3 μA for every 1 mW/cm2 decrease in light intensity. 
D)  the reverse current through the device will increase by 3 μA for every 1 mW/cm2 decrease in light intensity.

Question 20

Quadrant I triggering of a triac similar to SCR triggering) is accomplished by applying a gate potential when MT2 is more than MT1.

Accepted Answer

A)  positive; positive 
B)  positive; negative 
C)  negative; positive 
D)  negative; negative 
A)  positive; positive 
B)  positive; negative 
C)  negative; positive 
D)  negative; negative

Exam 20: Thyristors and Optoelectronics Devices

UJTs are used almost exclusively as

A photodiode has a rating of s = 1200 nm. What is the optimum operating frequency for the device?

The silicon unilateral switch SUS) is forced into forward conduction when VAK exceeds the rating of the device.

The forward operating curve of the SCR is identical to that for the SUS.

An SCR has a circuit fusing rating of 28 A2s. Will the device be destroyed if it is subjected to a 25 A surge that lasts for 50 ms?

The solid-state relay contains an internal

An SCR has a circuit fusing rating of 36 A2s. How long can the device withstand a 120 A surge?

Photodiodes are normally biased.

False triggering can be prevented by a

An object that blocks light is referred to as being

The speed of light c) is .

Light current through a photodiode is generally less than dark current.

The amount of light per unit area that is received by a photodetector is called

Once an SUS is forced into forward conduction, it continues to conduct until IF drops below the rating of the device.

A PUT has a value of VGK = +8 V. What value of VAK is needed to trigger the device into conduction?

The primary difference between the diac and the SUS is the fact that

What are the two methods that are commonly used to return an SUS to its nonconducting state?

What is the wavelength of a 200 THz signal?

A photo-detector has a sensitivity rating of 3 μA/mW/cm2. This means that

Quadrant I triggering of a triac similar to SCR triggering) is accomplished by applying a gate potential when MT2 is more than MT1.

Fundamental Solid-State Principles

Diodes

Common Diode Applications: Basic Power Supply Circuits

Common Diode Applications: Clippers, Clampers, Voltage Multipliers, and Displays

Special Applications Diodes

Bipolar Junction Transistors

DC Biasing Circuits

Introduction to Amplifiers

Common-Emitter Amplifiers

Other BJT Amplifiers

Power Amplifiers

Field-Effect Transistors

Mosfets

Amplifier Frequency Response

Operational Amplifiers

Additional Op-Amp Applications

Tuned Amplifiers

Oscillators

Solid-State Switching Circuits

Discrete and Integrated Voltage Regulators

Filters