Part 3 | Industrial Electronics

D

Referred to a bidirectional trigger diode.

a. Triac

b. UJT

c. BJT

d. Diac

B

Voltage required to turn on any thyristor.

a. Trigger voltage

b. Breakover voltage

c. Barrier voltage

d. Supply voltage

B

Also known as a four-layer diode.

a. Diac

b. Shockley diode

c. Zener diode

d. FET

B

The thyristor counterpart of the unijunction transistor.

a. UJT

b. PUT

c. SBS

d. SCS

A

Minimum current required to keep a thyristor “on”.

a. Holding current

b. Trigger current

c. Supply current

d. Collector current

D

A unidirectional-three terminal device, the most popular of thyristors.

a. SCS

b. Triac

c. UJT

d. SCR

B

The angle of an AC supply voltage during which an SCR is “off”.

a. Conduction angle

b. Firing delay angle

c. Right angle

d. Off angle

A

Thyristors are most often used as

a. Switches

b. Amplifiers

c. Buffers

d. Decoders

C

The total internal series resistance of the UJT.

a. Bulk’s resistance

b. Total resistance

c. Interbase resistance

d. RIS

A

The most popular and typical breakover voltage of a diac.

a. 32 V

b. 16 V

c. 8 V

d. 4 V

C

The peak voltage of a PUT is

a. VD + VBB

b. VG + VBB

c. VD + VG

d. VBB

B

A UJT has η = 0.65 and is connected to a 20 V supply. What is its VEB1?

a. 12 V

b. 13.6 V

c. 12.7 V

d. 14 V

A

The three terminal semiconductor device that acts in either direction.

a. Triac

b. SCR

c. Diac

d. SCS

A

The P of PUT stands for

a. Programmable

b. Performance

c. Peak

d. Post

D

The terminals of a UJT are

a. Gate, Anode, Cathode

b. Anode, Cathode

c. Emitter, Base

d. Emitter, Base1, Base2

C

The lowest current that can prevent the transition of a UJT from conduction to blocking region.

a. Switching current

b. Emitter current

c. Valley current

d. Peak current

C

The SCS has how many gate terminals?

a. 0

b. 1

c. 2

d. 3

B

What device has two terminals connected in inverse-parallel that pass in two directions?

a. Triac

b. Diac

c. Shockley

d. SCR

C

What is the breakover voltage of a PUT if it is connected to a 15 V supply across the gate terminal?

a. 10.7 V

b. 23.7 V

c. 15.7 V

d. 5.3 V

D

he gap between the forward blocking region and the forward conduction region.

a. Band gap

b. Switching region

c. Jump gap

d. Negative resistance region

D

The cathode of the PUT is the counterpart of which terminal in UJT?

a. Anode

b. Base2

c. Emitter

d. Base1

C

An electronic switch that has the highest single device current capacity and can withstand overloads better.

a. Thyratrons

b. Ignitrons

c. SCR

d. Triac

C

Group of devices with 4 or more semiconductor layers.

a. Transistors

b. Diodes

c. Thyristors

d. Op-Amps

B

Identify which of the following is a three layer device.

a. SCS

b. Diac

c. Triac

d. PUT

D

What device can be modeled by a diode and two resistors?

a. BJT

b. DIAC

c. SCR

d. UJT

D

A junction that is formed by adding controlled amounts of an impurity to the melt during crystal growth is termed as

a. Fused junction

b. Unijunction

c. Alloy junction

d. Doped junction

D

A triac is a ________.

a. 2 terminal switch

b. 2 terminal bilateral switch

c. 3 terminal unilateral switch

d. 3 terminal bidirectional switch

C

A thyristor equivalent of a thyratron tube is ________.

a. Diac

b. Triac

c. SCR

d. PUT

D

Which of the following describes a triac?

a. Conducts when not triggered

b. Conducts when not triggered in both directions

c. Conducts when triggered in one direction

d. Conducts when triggered in both direction

C

Minimum anode current to hold a thyristor at conduction.

a. Trigger

b. Maintaining current

c. Holding current

d. Threshold voltage

C

General term for semiconductor devices primarily used as switches.

a. Shockley

b. Thyratron

c. Thyristor

d. Relay

B

A two-terminal, unidirectional thyristor.

a. DIAC

b. Shockley

c. TRIAC

d. Diode

A

A thyristor is basically __________.

a. PNPN device

b. A combination of diac and triac

c. A set of SCRs

d. A set of SCR, diac and triac

D

What is the PNPN device with two gates?

a. Diac

b. Triac

c. SUS

d. SCS

C

Which device incorporates a terminal for synchronizing purposes?

a. Diac

b. Triac

c. SUS

d. SCR

B

An SCR is a _________.

a. Unijunction device

b. Device with three junctions

c. Device with four junctions

d. Device with two junctions

D

A thyristor can be turned off

a. By reducing the anode current below the holding current value

b. By reversing the anode voltage

c. Either a or b

d. Both a and b

A

Minimum duration of pulse triggering system for thyristors is ________.

a. At least 10 microseconds

b. At least 30 milliseconds

c. At least 10 milliseconds

d. At least 1 second

C

A device that cannot be triggered by voltage of either polarity is ________.

a. Diac

b. Triac

c. SCS

d. All of the above

D

Technically, what is dicing means?

a. Process of joining two diacs

b. Circuit of reducing noise

c. Device for reducing magnetic and radio interference

d. Process of breaking the silicon slice into chips

B

The term used to describe the process whereby two transistors with positive feedback are used to simulate the action of the thyristor.

a. Arcing

b. Latching

c. Damping

d. Switching

C

It is the minimum anode current to hold a thyristor at conduction.

a. Trigger

b. Maintaining current

c. Holding current

d. Threshold voltage

B

Electron tube containing mercury functioning as a rectifier.

a. Thyratron

b. Ignitron

c. Thyrector

d. SCR

C

How do you stop the conduction during which the SCR is also conducting?

a. Remove voltage gate

b. Increase cathode voltage

c. Interrupt anode current

d. Reduce gate current

B

A series RC connected in parallel with an SCR to eliminate false triggering is the _______.

A

Which are the three terminals of a TRIAC?

a. Gate, anode1 and anode2

b. Gate, source and sink

c. Base, emitter and collector

d. Emitter, base1 and base2

B

The term used to describe the process whereby two transistors with positive feedback are used to simulate the action of the thyristor.

a. Arcing

b. Latching

c. Damping

d. Switching

D

he minimum emitter to base voltage to trigger the UJT is the ________.

a. Forward breakover voltage

b. Trigger

c. Breakdown voltage

d. Peak voltage

D

The ratio of the emitter to base1 resistance to the interbase resistance of a UJT is called ________.

a. Aspect ratio

b. Current gain

c. Voltage gain

d. Intrinsic standoff ratio

B

For a UJT, it is the region between the peak and valley points as seen in its characteristics curve.

a. Active region

b. Negative resistance region

c. Trigger region

d. Saturation region