Question 1

The SCR is turned on by

Accepted Answer

A)  gate voltage. 
B)  increasing anode voltage. 
C)  reducing anode voltage. 
D)  forced commutation.

Question 2

When light strikes the gate of the device shown in Figure 13-34(a)

Accepted Answer

A)  +VCC drops to zero. 
B)  RL opens. 
C)  VCC is dropped across RL. 
D)  0 V is dropped across RL.

Question 3

The operation of a thyristor involves positive feedback.

Accepted Answer

A) True 
 B)False

Question 4

A semiconductor device that uses internal feedback to produce switching action is a ________.

Accepted Answer

A)  transistor 
B)  zener diode 
C)  thyristor 
D)  rectifier

Question 5

The only way to close a transistor latch circuit is by thermal runaway.

Accepted Answer

A) True 
 B)False

Question 6

The triac acts like two

Accepted Answer

A)  diacs in reverse parallel. 
B)  zeners in reverse parallel. 
C)  SCRs in reverse parallel. 
D)  JFETs in reverse parallel.

Question 7

The programmable unijunction transistor is considered programmable because

Accepted Answer

A)  the gate voltage can be determined by an external voltage divider. 
B)  the gate voltage is programmed using software. 
C)  the anode can be modified by adding resistors. 
D)  the cathode can be modified by adding resistors.

Question 8

A hybrid device that combines the low conduction loss of a BJT with the switching speed of a power MOSFET is

Accepted Answer

A)  a diaC. 
B)  an SCR. 
C)  a D-MOSFET. 
D)  an IGBT.

Question 9

If a high-speed switching transient appears on the supply voltage,its rate of rise can be reduced by using a

Accepted Answer

A)  zener diode 
B)  regulator circuit. 
C)  Schockley diode. 
D)  snubber circuit.

Question 10

IGBTs are effective solutions for

Accepted Answer

A)  low voltage and current applications at moderate frequencies. 
B)  high voltage and current applications at moderate frequencies. 
C)  high voltage and current applications at low frequencies. 
D)  low voltage and current applications at high frequencies.

Exam 13: Thyristors