Review Questions:



Review Questions:

Basic Electronics, Semiconductors, and Logic Circuits

© 1998 Charles Abzug

1. Think about, and be prepared to discuss, the difference in resolution between analog and digital systems, where resolution is defined as:

“the minimum difference that can be represented between successive values of the quantity measured”.

HINT: Resolution in digital systems depends upon the number of bits available to represent what is being measured. For example, an 8-bit sound card represents magnitude of the current to be driven through a loud-speaker in eight bits, while a 16-bit sound card has twice as many bits. How many different values can be represented in each case? If there is a fixed difference of 250 milliamps between the maximum and minimum values of current, then what is the approximate resolution of the 8-bit sound card, and of the 16-bit card? See also: Bebop to the Boolean Boogie, figures 1.4, 1.5, and 1.6.

2. If all the empty space were removed from the atoms of a camel, then it would be possible for the camel to pass through:

a) the Champs Elysee.

b) the keyhole in President Clinton’s office door.

c) the eye of a needle.

d) all of the above.

e) none of the above.

Explain your answer.

3. What is the number of electrons in the outermost subshell of:

|Sodium (Na) | |

|Carbon (C) | |

|Calcium (Ca) | |

|Argon (Ar) | |

|Aluminum (Al) | |

|Germanium (Ge) | |

|Boron (B) | |

|Phosphorus (P) | |

|Helium (He) | |

|Silicon (Si) | |

4. Indicate whether each substance listed is classed as a conductor, an insulator, or a semiconductor. Explain what class of materials each of the items listed belongs to (e.g., metal, inert gas, outer-subshell-has-4-electrons, etc).

Sodium

Silicon

Neon

Gold

Aluminum

Germanium

Copper

Epoxy Resin

Argon

Silver

Gallium Arsenide

5. What are the units of measurement for:

Electrical Current

Electrical Resistance

Electrical Resistivity

Electrical Conductance

Electrical Capacitance

Electrical Inductance

Electrical Voltage

6. What is Ohm’s Law? Kirchoff’s First Law? Kirchoff’s Second Law?

7. What is the equivalent resistance value, Requiv, of two resistors, R1 and R2, connected in series? In parallel?

8. What is the equivalent capacitance value, Cequiv, of two capacitors, C1 and C2, connected in series? In parallel?

9. What is the equivalent inductance value, Lequiv, of two inductors, L1 and L2, connected in series? In parallel?

10. Know well the prefix names and the abbreviations for all the quantities specified in Table 3.1 (page 21) of Bebop to the Boolean Boogie.

11. Define the term doping as it is used to describe an area of semiconductor circuit manufacture.

12. Explain what goes on in diffusion as the term is used to describe a part of the process of semiconductor circuit manufacture.

13. Switch representation of logic gates:

a) Draw a switch representation of a 5-input AND function. Produce both a diagram and a Truth Table. Label your switches A through E, and use 0 to indicate an Open switch, Off, or False, and 1 to indicate a Closed switch, On, or True.

b) Do the same for a 4-input OR function.

14. Diagrammatic representation of logic gates:

a) Draw a diagram and produce a Truth Table describing the operation of a 5-input logical NAND function. Label your inputs A through E, use 0 to indicate “F” or False, and use 1 to indicate “T” or True.

b) Do the same for a 4-input logical NOR function.

c) Do the same for a 3-input XOR function. NOTE that the n-input XOR function is also known as the odd function because the function has a value of 1 whenever an odd number of its input lines have the value of 1.

d) Do the same for a 4-input XNOR function. NOTE that the n-input XNOR function is also known as the even function because the function has a value of 1 whenever an even number of its input lines have the value of 1.

15. What do the acronyms MOSFET, PMOS, NMOS, and CMOS stand for?

16. Draw a schematic representation of a PMOS transistor. Of an NMOS transistor. For a PMOS transistor, what logic level (positive logic) applied to the gate of the transistor turns it on, and what logic level turns it off? For an NMOS transistor?

17. Draw the Truth Table, the logical symbol, and the CMOS transistor circuit for a NOT gate, and explain how the circuit works.

18. Draw the Truth Table, the logical symbol, and the CMOS transistor circuit for a Buffer gate, and explain how the circuit works.

19. Draw the Truth Table, the logical symbol, and the CMOS transistor circuit for a 2-input NAND gate, and explain how the circuit works. Do the same for a 3-input NAND gate. For a 4-input NAND gate. Write a mathematical expression that describes the number of transistors in an n-input NAND gate as a function of the number of inputs n.

20. Draw the Truth Table, the logical symbol, and the CMOS transistor circuit for a 2-input NOR gate, and explain how the circuit works. Do the same for a 3-input NOR gate. For a 4-input NOR gate. Write a mathematical expression that describes the number of transistors in an n-input NOR gate as a function of the number of inputs n.

21. Draw the Truth Table, the logical symbol, and the CMOS transistor circuit for a 2-input AND gate, and explain how the circuit works. Do the same for a 3-input AND gate. For a 4-input AND gate. Write a mathematical expression that describes the number of transistors in an n-input AND gate as a function of the number of inputs n.

22. Draw the Truth Table, the logical symbol, and the CMOS transistor circuit for a 2-input OR gate, and explain how the circuit works. Do the same for a 3-input OR gate. For a 4-input OR gate. Write a mathematical expression that describes the number of transistors in an n-input OR gate as a function of the number of inputs n.

23. Single-Variable Boolean Logic:

a) A·0 = ?

b) A·1 = ?

c) A+0 = ?

d) A+1 = ?

e) A·A = ?

f) A+A = ?

g) A·~A = ?

h) A+~A = ?

24. Boolean Logic: Multi-Variable Identities

a) A·B = ? (commutative rule)

b) A+B = ? (commutative rule)

i) A·(B·C) = ? (associative rule)

j) A+(B+C) = ? (associative rule)

k) A·(B+C) = ? (distributive rule)

l) A+(B·C) = ? (distributive rule)

25. Construct a Truth Table to demonstrate each of the following Boolean Identities:

a) A+(A·B) = A

b) A·(A+B) = A

c) (A·B) + (A·~B) = A

d) (A+B)·(A+~B) = A

e) A+(~A·B) = A+B

f) A·(~A+B) = A·B

26. State each of the two DeMorgan Theorems, and prove both of them by construction of Truth Tables.

Answers to Selected Questions:

Question 3:

|Sodium (Na) |1 |

|Carbon (C) |4 |

|Calcium (Ca) |2 |

|Argon (Ar) |8 |

|Aluminum (Al) |3 |

|Germanium (Ge) |4 |

|Boron (B) |3 |

|Phosphorus (P) |5 |

|Helium (He) |2 |

|Silicon (Si) |4 |

Partial Answer to Question 4:

Sodium: Conductor (it is a metal)

Silicon: Semiconductor

Neon: Insulator (it is an inert gas)

Gold: Conductor

Aluminum: Conductor

Germanium: Semiconductor

Copper: Conductor

Epoxy Resin: Insulator (organic thermosetting plastic)

Argon: Insulator

Silver: Conductor

Gallium Arsenide: Semiconductor

Question 13a: Compare Figures 5.1 and 5.5a in Bebop to the Boolean Boogie.

Question 13b: Compare Figures 5.2 and 5.5b in Bebop to the Boolean Boogie.

Question 14: Compare Figure 5.7 top, middle, and bottom in Bebop to the Boolean Boogie.

Question 17: See Figure 6.1 in Bebop to the Boolean Boogie.

Question 18: See Figure 6.2 in Bebop to the Boolean Boogie.

Question 19: See Figure 6.4 in Bebop to the Boolean Boogie.

Question 20: See Figure 6.7 in Bebop to the Boolean Boogie.

Question 21: See Figure 6.6 in Bebop to the Boolean Boogie.

Question 22: See Figure 6.8 in Bebop to the Boolean Boogie.

Question 23:

(a) 0 Figure 9.2 upper left

(b) A Figure 9.2 lower left

(c) A Figure 9.2 upper right

(d) 1 Figure 9.2 lower right

(e) A Figure 9.3 left

(f) A Figure 9.3 right

(g) 0 Figure 9.4 left

(h) 1 Figure 9.4 right

Question 24:

(a) B·A (Figure 9.6 left)

(b) B+A (Figure 9.6 right)

(c) (A·B)·C (Figure 9.7 top)

(d) (A+B)+C (Figure 9.7 bottom)

(e) (A·B) + (A·C) (Figure 9.8)

(f) (A+B)·(A+C) (Figure 9.9)

Question 25: See Figure 9.10 in Bebop to the Boolean Boogie.

Question 26:

a) A·B = ~(~A + ~B) See Figure 9.11 and the top half of Figure 9.12 in Bebop to the Boolean Boogie.

b) A+B = ~(~A · ~B) See the bottom half of Figure 9.12 in Bebop to the Boolean Boogie.

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