Floyd Self-test in Thyristors

This is the Self-test in Chapter 11: Thyristors from the book Electronic Devices Conventional Current Version, 9th edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

Floyd Self-test Chapter 11 Topic Outline

• Floyd Self-test in The Four-Layer Diode
• Floyd Self-test in The Silicon-Controlled Rectifier (SCR)
• Floyd Self-test in SCR Applications
• Floyd Self-test in The Diac and Triac
• Floyd Self-test in The Silicon-Controlled Switch (SCS)
• Floyd Self-test in The Unijunction Transistor (UJT)
• Floyd Self-test in The Programmable Unijunction Transistor (PUT)

Start Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. A thyristor has

• (a) two pn junctions
• (b) three pn junctions
• (c) four pn junctions
• (d) only two terminals

2. Common types of thyristors include

• (a) BJTs and SCRs
• (b) UJTs and PUTs
• (c) FETs and triacs
• (d) diacs and triacs

3. A 4-layer diode turns on when the anode-to-cathode voltage exceeds

• (a) 0.7 V
• (b) the gate voltage
• (c) the forward-breakover voltage
• (d) the forward-blocking voltage

4. Once it is conducting, a 4-layer diode can be turned off by

• (a) reducing the current below a certain value
• (b) disconnecting the anode voltage
• (c) answers (a) and (b)
• (d) neither answer (a) nor (b)

5. An SCR differs from the 4-layer diode because

• (a) it has a gate terminal
• (b) it is not a thyristor
• (c) it does not have four layers
• (d) it cannot be turned on and off

6. An SCR can be turned off by

• (a) forced commutation
• (b) a negative pulse on the gate
• (c) anode current interruption
• (d) answers (a), (b), and (c)
• (e) answers (a) and (c)

7. In the forward-blocking region, the SCR is

• (a) reverse-biased
• (b) in the off state
• (c) in the on state
• (d) at the point of breakdown

8. The specified value of holding current for an SCR means that

• (a) the device will turn on when the anode current exceeds this value
• (b) the device will turn off when the anode current falls below this value
• (c) the device may be damaged if the anode current exceeds this value
• (d) the gate current must equal or exceed this value to turn the device on

9. The diac is

• (a) a thyristor
• (b) a bilateral, two-terminal device
• (c) like two parallel 4-layer diodes in reverse directions
• (d) answers (a), (b), and (c)

10. The triac is

• (a) like a bidirectional SCR
• (b) a four-terminal device
• (c) not a thyristor
• (d) answers (a) and (b)

11. The SCS differs from the SCR because

• (a) it does not have a gate terminal
• (b) its holding current is less
• (c) it can handle much higher currents
• (d) it has two gate terminals

12. The SCS can be turned on by

• (a) an anode voltage that exceeds forward-breakover voltage
• (b) a positive pulse on the cathode gate
• (c) a negative pulse on the anode gate
• (d) either (b) or (c)

13. The SCS can be turned off by

• (a) a negative pulse on the cathode gate and a positive pulse on the anode gate
• (b) reducing the anode current to below the holding value
• (c) answers (a) and (b)
• (d) a positive pulse on the cathode gate and a negative pulse on the anode gate

14. Which of the following is not a characteristic of the UJT?

• (a) intrinsic standoff ratio
• (b) negative resistance
• (c) peak-point voltage
• (d) bilateral conduction

15. The PUT is

• (a) much like the UJT
• (b) not a thyristor
• (c) triggered on and off by the gate-to-anode voltage
• (d) not a four-layer device

Complete List of Floyd Self-test in Electronic Devices

Floyd Self-test in Electronic Devices

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