# 計算機概論 Homework#2 Ch. 3 ```計算機概論
Homework#2
Ch. 3
3.1 In the following table, write whether each type of transistor will act as an open
circuit or a closed circuit
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3.2 Replace the missing parts in the circuit below with either a wire or no wire to
give the output OUT a logical value of 0 when the input IN is a logical 1.
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3.5 Complete a truth table for the transistor-level circuit in Figure 3.34.
Figure 3.34 Diagram for Exercise 3.5
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3.6 For the transistor-level circuit in Figure 3.35, fill in the truth table. What is Z in
terms of A and B?
Figure 3.35 Diagram for Exercise 3.6
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;
3.7 The circuit below has a major flaw. Can you identify it? Hint: Evaluate the
circuit for all sets of inputs.
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There is short circuit (path from Power to Ground) when either A = 1 and B = 0
or A = 0 and B = 1.
3.9 Fill in the truth table for the logical expression NOT(NOT(A) OR NOT(B)).
What single logic gate has the same truth table?
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AND gate has the same truth table.
3.10 Fill in the truth table for a two-input NOR gate.
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3.12 Following the example of Figure 3.11a, draw the gate-level schematic of a threeinput decoder. For each output of this decoder, write the input conditions under which
that output will be 1.
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A
B
C
A,B,C = 0 0 0
A,B,C = 0 0 1
A,B,C = 0 1 0
A,B,C = 0 1 1
A,B,C = 1 0 0
A,B,C = 1 0 1
A,B,C = 1 1 0
A,B,C = 1 1 1
3.16 Given the following truth table, generate the gate-level logic circuit, using the
implementation algorithm referred to in Section 3.3.4.
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A
B
C
Z
3.22 Implement a 4-to-1 mux using only 2-to-1 muxes making sure to properly
connected all of the terminals. Remember that you will have 4 inputs, 2 control
signals, and 1 output. Write out the truth table for this circuit.
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