Question 1

A DIAC is a three-layer, two-junction semiconductor device that has only two leads.

Accepted Answer

A) True 
 B)False  True

Question 2

A device that can control ac power, because it can conduct in either direction, is called a triac.

Accepted Answer

A) True 
 B)False  True

Question 3

Which triac triggering mode is the most sensitive?

Accepted Answer

A)   1
B)   2
C)   3
D)   4 A

Question 4

______________ are primarily used in power control circuits.

Accepted Answer

The answer of ______________ are primarily used in power control...

Question 5

Along with transistors and FETs, thyristors can be used for amplification.

Accepted Answer

A) True 
 B)False

Question 6

A bi-directional semiconductor device that remains in a nonconducting state until the forward breakover voltage is reached is a(n)

Accepted Answer

A)   DIAC
B)   SCR
C)   triac
D)   E-MOSFET

Question 7

Because a triac requires different gate currents for each mode of operation, it is ______________.

Accepted Answer

The answer of Because a triac requires different gate currents...

Question 8

The DIAC is often used to provide a sharp trigger current pulse that can be used to turn on another thyristor known as a

Accepted Answer

A)   SCR
B)   silicon-controlled switch
C)   triac
D)   JFET

Question 9

Thyristors can operate only in the switching mode, where they act like either an open or closed switch.

Accepted Answer

A) True 
 B)False

Question 10

What component controls the frequency of the UJT relaxation oscillator?

Accepted Answer

A)   D4
B)   D5
C)   R2
D)   RT

Question 11

Which triac triggering mode is the most sensitive?

Accepted Answer

A)   1
B)   2
C)   3
D)   4

Question 12

An SCR operates in the same way as a rectifier diode.

Accepted Answer

A) True 
 B)False

Question 13

An SCR differs from an ordinary rectifier diode in that the SCR will remain in a(n) ______________ state, although forward biased, until the forward breakover voltage is reached.

Accepted Answer

The answer of An SCR differs from an ordinary rectifier...

Question 14

The ______________ transistor is a three-terminal semiconductor device that has only one p-n junction.

Accepted Answer

The answer of The ______________ transistor is a three-terminal semiconductor...

Question 15

What is the function of D5 in the circuit shown in Figure 32-14?

Accepted Answer

A)   rectifies ac
B)   provides a positive trigger to the SCR
C)   provides voltage for the UJT
D)   provides ac to the load

Question 16

Thyristors (can/cannot) be used for amplification.

Accepted Answer

The answer of Thyristors (can/cannot) be used for amplification....

Question 17

DIACs are primarily used in power control circuits.

Accepted Answer

A) True 
 B)False

Question 18

Thyristors are semiconductor devices that are specifically designed for use in high-power switching applications.

Accepted Answer

A) True 
 B)False

Question 19

The region where the voltage drop across a DIAC decreases as the DIAC current increases is called

Accepted Answer

A)   reverse bias region
B)   negative resistance region
C)   negative breakdown region
D)   reverse resistance region

Question 20

Once an SCR is turned on by gate current, the gate

Accepted Answer

A)   turns it off right away
B)   turns it off after the time set up by R and C
C)   loses all control
D)   current must be removed

Exam 34: Thyristors

A DIAC is a three-layer, two-junction semiconductor device that has only two leads.

A device that can control ac power, because it can conduct in either direction, is called a triac.

Which triac triggering mode is the most sensitive?

______________ are primarily used in power control circuits.

Along with transistors and FETs, thyristors can be used for amplification.

A bi-directional semiconductor device that remains in a nonconducting state until the forward breakover voltage is reached is a(n)

Because a triac requires different gate currents for each mode of operation, it is ______________.

The DIAC is often used to provide a sharp trigger current pulse that can be used to turn on another thyristor known as a

Thyristors can operate only in the switching mode, where they act like either an open or closed switch.

What component controls the frequency of the UJT relaxation oscillator?

Which triac triggering mode is the most sensitive?

An SCR operates in the same way as a rectifier diode.

An SCR differs from an ordinary rectifier diode in that the SCR will remain in a(n) ______________ state, although forward biased, until the forward breakover voltage is reached.

The ______________ transistor is a three-terminal semiconductor device that has only one p-n junction.

What is the function of D₅ in the circuit shown in Figure 32-14?

Thyristors (can/cannot) be used for amplification.

DIACs are primarily used in power control circuits.

Thyristors are semiconductor devices that are specifically designed for use in high-power switching applications.

The region where the voltage drop across a DIAC decreases as the DIAC current increases is called

Once an SCR is turned on by gate current, the gate