#FocusonExam: Computer Science – O’leve – 9th April 2020
THE NOT GATE
characteristics of a NOT gate:
The graphical symbols of a logic gate is given below:
How it operates
The NOT gate functions like this:
when it receives 1 as input, it gives 0 as output and when it receives 0 as input, it gives out 1 as output.
TRUTH TABLE
The truth table is a tabular representation of how a gate operates.
A truth table is produced by writing all possible values an input of a gate can take, then deducing the output from its behavior.
THE NOT GATE
Truth table
Formative evaluation 1
1.The NOT gate has at least one input channel
2.If the input of the NOT gate is the value 0, then its output will be 1.
3.If the input of the NOT gate is the variable A, then its output will be
4.The graphical symbol used to identify the NOT gate is given by:
Solution to Exercise 1
1.False
2.True.
3.False
4.The graphical symbol used to identify the NOT gate is given by:
Formative evaluation 2
1.Match each input with the corresponding output:
2.What will be the output of the NOT gate when the input
is 2 ? Explain your answer.
- Draw the truth table of the NOT gate.
Summary
So far we’ve seen that the NOT gate takes one input, puts a bar on any variable it receives as input and sends out as output. It is called an inverter since when the input carries the value 0, it gives out 1 and when it is 1, it gives out zero.