The NOT gate

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The NOT gate

Name:
Date:
Class:
A

Quick Questions

Shade in the A or B circle for each question.

1. A NOT gate has how many inputs?
A Two inputs
B One input
2. A NOT gate receives the input 1. What is the output?
A 0
B 1
3. A NOT gate receives the input 0. What is the output?
A 1
B 0
4. Which is the correct logic expression for a NOT gate with input A and output X?
A X = A NOT
B X = NOT A
5. Which symbol is used for a NOT gate?
A A triangle with a small circle
B A D-shape with a small circle
B

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left columnRight column
1X = NOT A AThe output X is the opposite of input A: when A is 0, X is 1, and when A is 1, X is 0.
2A = 1, X = NOT A, so X = 0 BA | X 0 | 1 1 | 0
3A NOT gate has only one input, so its two-row truth table lists just A = 0 and A = 1 with the output X in the next column. CA NOT gate turns an input of 1 into an output of 0.
4The NOT gate is drawn as a triangle with a small circle on its output. It is also called an inverter because it inverts the input. DThe output X is copied from the input A. A NOT gate should output the opposite, so 0 gives 1 and 1 gives 0.
5A | X 0 | 0 1 | 1 EA --|>o-- X
6X = NOT (A, B) FNOT has only one input, so it cannot be applied to two inputs A and B at once. It should be X = NOT A.
C

Definitions

NOT
D

Fill in the Blanks

Complete each line of code by filling in the missing parts.

1.
X = ___ A
2.
X = NOT _
3.
A X 0 _ 1 0
4.
A X 0 1 1 _
5.
NOT gate: _ input, 1 output
E

Spot the Error

Shade in the letter of the line that contains an error.

Question 1
A Truth table for NOT gate
B A | X
C 0 | 1
D 1 | 1
Question 2
A Gate: NOT
B Inputs: 1
C Expression: X = A NOT
D Output: opposite of A
Question 3
A A = 1
B X = NOT A, B
C PRINT X
Question 4
A A X
B 0 0
C 1 0
Question 5
A NOT gate symbol:
B Triangle shape
C Small circle at the output
D Two inputs, one output

Answer Key

The NOT gate
Section A: Quick Questions
Q1
B — One input
Q2
A — 0
Q3
A — 1
Q4
B — X = NOT A
Q5
A — A triangle with a small circle
Section B: Match the Pairs
Q1
X = NOT A → The output X is the opposite of input A: when A is 0, X is 1, and when A is 1, X is 0.
Q2
A = 1, X = NOT A, so X = 0 → A NOT gate turns an input of 1 into an output of 0.
Q3
A NOT gate has only one input, so its two-row truth table lists just A = 0 and A = 1 with the output X in the next column. → A | X 0 | 1 1 | 0
Q4
The NOT gate is drawn as a triangle with a small circle on its output. It is also called an inverter because it inverts the input. → A --|>o-- X
Q5
A | X 0 | 0 1 | 1 → The output X is copied from the input A. A NOT gate should output the opposite, so 0 gives 1 and 1 gives 0.
Q6
X = NOT (A, B) → NOT has only one input, so it cannot be applied to two inputs A and B at once. It should be X = NOT A.
Section C: Definitions
Q1
NOT — A logic gate with one input that outputs the opposite value: 0 becomes 1 and 1 becomes 0. It is drawn as a triangle with a small circle and written X = NOT A.
Section D: Fill in the Blanks
Q1
X = NOT A
Q2
X = NOT A
Q3
A X 0 1 1 0
Q4
A X 0 1 1 0
Q5
NOT gate: 1 input, 1 output
Section E: Spot the Error
Q1
D — A NOT gate outputs the opposite of its input. When A is 1, X must be 0, so the row should be 1 | 0.
Q2
C — In a logic expression NOT is written before the input it inverts. The expression should be X = NOT A.
Q3
B — A NOT gate has only one input, so it cannot take A and B. The line should be X = NOT A.
Q4
B — NOT turns 0 into 1. When A is 0 the output X must be 1, so the row should be 0 1.
Q5
D — A NOT gate (inverter) has just one input and one output. The line should say One input, one output.