THYRISTORS

Question 1

class of semiconductor devices characterized by 4-layers of alternating p and n materials. Four-layer devices act as either open or closed switches.

Answer 1

-THYRISTORS

Question 2

It is a rectifier constructed of silicon material with a third terminal for control purposes.

Answer 2

-SILICON CONTROLLED RECTIFIER

Question 3

resistance is typically 100 kOhms or more.

Answer 3

-REVERSE

Question 4

resistance of the SCR is typically 0.01 to 0.1 ohm.

Answer 4

-DYNAMIC

Question 5

SCR can be turned on by exceeding the forward breakover voltage or

Answer 5

-GATE CURRENT

Question 6

Turning off SCR

Answer 6

1. Anode current interruption
2.  Forced commutation

Question 7

times of of SCRs are typically 0.1 to 1 microsecond.

Answer 7

-TURN ON

Question 8

times of SCRs are typically 5 to 30 microsecond.

Answer 8

-TURN OFF

Question 9

is that voltage above which the SCR enters the conduction region.

Answer 9

-FORWARD BREAKOVER VOLTAGE

Question 10

is the value of gate current necessary to switch the SCR from the forward-blocking region to the forward conduction region under specified conditions.

Answer 10

-GATE TRIGGER CURRENT

Question 11

is that value of current below which the SCR switches from the conduction state to the forward blocking region under stated conditions.

Answer 11

-HOLDING CURRENT

Question 12

are the regions corresponding to the open circuit condition for the controlled rectifier which block the flow of charge (current) from anode to cathode.

Answer 12

-FORWARD AND REVERSE BLOCKING

Question 13

is equivalent to the Zener or avalanche region of the fundamental two-layer semiconductor diode.

Answer 13

-REVERSE BREAKDOWN VOLTAGE

Question 14

The characteristics of the device are essentially the same as those for the SCR.

Answer 14

-SILICON CONTROLLED SWITCH

Question 15

can be used to turn the device either on or off.

Answer 15

-ANODE GATE CONNECTION

Question 16

a negative pulse must be applied to the anode gate terminal.

Answer 16

-TURN ON THE DEVICE

Question 17

while a positive pulse is required to

Answer 17

-TURN OFF THE DEVICE

Question 18

An advantage of the SCS over a corresponding SCR is the

Answer 18

-REDUCED TURN OFF TIME

Question 19

Turn off time is typically within the range 1 to 10 microseconds for the

Answer 19

-SILICON CONTROLLED SWITCH

Question 20

Turn off time is typically 5 to 30 microseconds for the

Answer 20

-SILICON CONTROLLED RECTIFIER