1. Binary Logic

2. Binary
1’s and 0’s
On or Off
High or Low voltage levels

3. Truth Tables & Logic Gates
A truth table is a diagram that shows all possible logical inputs and their associated outputs.
Logic gates are circuits that are used to perform a logical operation in computing.

4. NOT Gate
The NOT gate is the simplest gate used in computing as it has a single input and output that perform the following logic:
when the input is 0, the output will be 1
when the input is 1, the output will be 0
Note that the NOT function output is the inverse (or opposite) of the input; this logical information can be expressed in a truth table as shown below: A R 1
The symbol used to represent a NOT gate is shown in the diagram below.
Output R
Input A

5. The OR gate has two or more inputs and the output will be:
0 when ALL the inputs are 0
1 when ANY or ALL inputs are 1
Note that the OR function output is true if either or both inputs are true; this logical information can be expressed in a truth table as shown below: A B R 1
The symbol used to represent an OR gate is shown in the diagram below.
Output R A
Inputs B

6. AND Gate
The AND gate has two or more inputs and the output will be:
1 when ALL the inputs are 1
0 when ANY or ALL inputs are 0
Note that the AND function output is true if all inputs are true; this logical information can be expressed in a truth table as shown below: A B R 1
The symbol used to represent an AND gate is shown in the diagram below.
Output R A
Inputs B

7. NOT (A) AND NOT (B) Draw diagram and truth table onto paper A B A B R1

8. June 2014 – Qu 7
Solution A B
NOT (a AND b) 1