This is the Multiple Choice Questions (MCQs) in Chapter 30: Basic Digital Principles from the book Teach Yourself Electricity and Electronics, 5th edition by Stan Gibilisco. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.

### Begin the Test

1. The value of the decimal number 23 in binary form is:

- A. 1011.
- B. 110111.
- C. 10111.
- D. 11100.

2. The binary number 110001 represents the digital number:

- A. 49.
- B. 25.
- C. 21.
- D. 13.

3. The fifth digit from the right in a binary number carries a decimal value of:

- A. 64.
- B. 32.
- C. 24.
- D. 16.

4. The largest possible decimal number that can be represented by six binary digits (bits) is:

- A. 256.
- B. 128.
- C. 64.
- D. 63.

5. Which of the following voltages could normally represent a 1 in positive logic?

- A. 0 V.
- B. + 1 V.
- C. + 4 V.
- D. + 12 V.

6. Which of the following voltages might normally represent a 1 in negative logic?

- A. 0 V.
- B. + 4 V.
- C. + 6 V.
- D. + 12 V.

7. If X is low, what is the state of X AND Y?

- A. There is not enough information to tell.
- B. Low.
- C. High.
- D. This logic statement makes no sense.

8. If X is high, what is the state of X NOR Y?

- A. There is not enough information to tell.
- B. Low.
- C. High.
- D. This logic statement makes no sense.

9. If X and Y are both high, what is the state of X NAND Y?

- A. There is not enough information to tell.
- B. Low.
- C. High.
- D. This logic statement makes no sense.

10. If X is high and Y is low, what is the state of X NOT Y?

- A. There is not enough information to tell.
- B. Low.
- C. High.
- D. This logic statement makes no sense.

11. A logic circuit has four inputs W, X, Y, and Z. How many possible input combinations are there?

- A. 4.
- B. 8.
- C. 16.
- D. 32.

12. Data sent along a single line, one bit after another, is called:

- A. Serial.
- B. Synchronous.
- C. Parallel.
- D. Asynchronous.

13. If X = 1 and Y = 1, then X + YZ is:

- A. Always 0.
- B. 0 if Z = 0, and 1 if Z = 1.
- C. 1 if Z = 0, and 0 if Z = 1.
- D. Always 1.

14. If X = 0 and Y = 1, then X(Y + Z) is:

- A. Always 0.
- B. 0 if Z = 0, and 1 if Z = 1.
- C. 1 if Z = 0, and 0 if Z = 1.
- D. Always 1.

15. An advantage of a J-K over an R-S flip-flop is that:

- A. The J-K flip-flop is faster.
- B. The J-K can attain more states.
- C. The J-K always has predictable outputs.
- D. No! An R-S flip-flop is superior to a J-K.

16. In positive-edge triggering, the change of state occurs when:

- A. The pulse level is high.
- B. The pulse level is going from high to low.
- C. The pulse level is going from low to high.
- D. The pulse level is low.

17. The inputs of an R-S flip-flop are known as:

- A. Low and high.
- B. Asynchronous.
- C. Synchronous.
- D. Set and reset.

18. When both inputs of an R-S flip-flop are 0:

- A. The outputs stay as they are.
- B. Q = 0 and -Q = 1.
- C. Q = 1 and -Q = 0.
- D. The resulting outputs can be absurd.

19. When both inputs of an R-S flip-flop are 1:

- A. The outputs stay as they are.
- B. Q = 0 and -Q = 1.
- C. Q = 1 and -Q = 0.
- D. The resulting outputs can be absurd.

20. A frequency synthesizer makes use of

- A. An OR gate.
- B. A divider.
- C. The octal numbering system.
- D. The hexadecimal numbering system.

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