The AND gate

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The AND gate

Name:
Date:
Class:
A

Quick Questions

Shade in the A or B circle for each question.

1. An AND gate outputs 1 when...
A At least one input is 1
B Both inputs are 1
2. Which output column is correct for an AND gate (rows A,B = 00, 01, 10, 11)?
A 0 0 0 1
B 0 1 1 1
3. Which logic expression describes an AND gate?
A X = A AND B
B X = A OR B
4. What shape is the standard AND gate symbol?
A A triangle with a small circle on the tip
B A D shape
5. A = 1 and B = 0 go into an AND gate. What is X?
A X = 0
B X = 1
B

Match the Pairs

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

Left columnRight column
1X = A AND B AThe expression is incomplete. An AND gate has two inputs, so it needs a second input after AND.
2A=0 B=1 -> X=0 BAn AND gate gives 0 when only one of its inputs is 1
3The output column of an AND gate truth table for the input rows 00, 01, 10, 11 CThis is the output of an OR gate, not an AND gate. AND should be 0 0 0 1 because it needs both inputs to be 1.
4An AND gate has two inputs and outputs 1 only when both inputs are 1 DThe expression for an AND gate: X is 1 only when A and B are both 1
5X: 0 1 1 1 EA=1 B=1 -> X=1
6X = A AND FX: 0 0 0 1
C

Definitions

AND
D

Fill in the Blanks

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

1.
X = A ___ B
2.
X = A AND _
3.
A=1, B=1 -> X = A AND B = _
4.
A=1, B=0 -> X = A AND B = _
5.
Output column for AND: 0 0 0 _
E

Spot the Error

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

Question 1
A A B | X
B 0 0 | 0
C 0 1 | 0
D 1 0 | 1
E 1 1 | 1
Question 2
A X = A OR B
B A = 1
C B = 0
D X = 0
Question 3
A INPUT A
B INPUT B
C X ← A NAND B
D OUTPUT X
Question 4
A AND gate symbol
B Shape: triangle and circle
C Inputs: 2
D Output: 1
Question 5
A Row 0 0 gives X = 0
B Row 0 1 gives X = 0
C Row 1 0 gives X = 0
D Row 1 1 gives X = 0

Answer Key

The AND gate
Section A: Quick Questions
Q1
B — Both inputs are 1
Q2
A — 0 0 0 1
Q3
A — X = A AND B
Q4
B — A D shape
Q5
A — X = 0
Section B: Match the Pairs
Q1
X = A AND B → The expression for an AND gate: X is 1 only when A and B are both 1
Q2
A=0 B=1 -> X=0 → An AND gate gives 0 when only one of its inputs is 1
Q3
The output column of an AND gate truth table for the input rows 00, 01, 10, 11 → X: 0 0 0 1
Q4
An AND gate has two inputs and outputs 1 only when both inputs are 1 → A=1 B=1 -> X=1
Q5
X: 0 1 1 1 → This is the output of an OR gate, not an AND gate. AND should be 0 0 0 1 because it needs both inputs to be 1.
Q6
X = A AND → The expression is incomplete. An AND gate has two inputs, so it needs a second input after AND.
Section C: Definitions
Q1
AND — A logic gate with two inputs that outputs 1 only when both inputs are 1; otherwise it outputs 0. Written X = A AND B, drawn as a D shape, with truth table output 0 0 0 1.
Section D: Fill in the Blanks
Q1
X = A AND B
Q2
X = A AND B
Q3
A=1, B=1 -> X = A AND B = 1
Q4
A=1, B=0 -> X = A AND B = 0
Q5
Output column for AND: 0 0 0 1
Section E: Spot the Error
Q1
D — An AND gate only outputs 1 when both inputs are 1. When A is 1 and B is 0, X must be 0, so the row should be 1 0 | 0.
Q2
A — The expression for an AND gate is X = A AND B. Using OR would give X = 1 for these inputs, which does not match the final line.
Q3
C — NAND is a different gate whose output is the opposite of AND. The AND gate expression should be X ← A AND B.
Q4
B — The AND gate is drawn as a D shape. A triangle with a small circle is the symbol for a NOT gate.
Q5
D — Both inputs are 1 in the last row, so an AND gate outputs 1. The line should be Row 1 1 gives X = 1.