[CSig] Logic Gates Introduction

[CSig] Logic Gates Introduction

by Andy tsui

​Objectives

• ​Define and understand the functions of the logic gates

• ​Identify and use the standard symbols for logic gates

Watch video about logic gate​

... And answer questions afterwards​

​https://youtu.be/ZoqMiFKspAA

Multiple Select

Choose the correct ones

• Information in computer is represented by electrical signal

• Digital signal can be on or off (1 or 0) only

• Computer is composed of many circuits

• The circuit in the computer is designed to process digital signal

Multiple Choice

The circuit symbol is called "NOT", which flips the input. So if the input is a 0, what is the output?

• 1

• 0

• can be any

• 10

Multiple Select

The one in the image is called an "AND" circuit. Which of the following cases will produce 1 as output?

• 1 AND 0

• 0 AND 0

• 1 AND 1

• 0 AND 1

Multiple Choice

According to the video, what moves "almost" as fast as light?

• Electricity

• energy

• logica

• circuits

​Logic Gates

• ​Computer is an electronic device which designed to process digital signal

• Computer is made with (millions of) different logic gates

• ​Connecting logic gates allows computers to manipulate the input data and eventually produce complicated results (e.g. math operations)

​NOT gate

• ​Invert the input signal

• ​such that:

  • ​NOT (1) => 0

  • ​NOT (0) => 1

• ​or we can say:

  • ​NOT True => False

Fill in the Blanks

What will be the OUTPUT value of Y, if A = 1 ?

​AND Gate

• ​AND gate only gives 1 if both A AND B is 1

​OR Gate

• ​OR Gate gives 1 except both inputs are 0

​Combining Logic Gates

​Consider the following circuit

​Create truth table to work out the answer. Need to create intermediate labels to help.

​Example 2:

​Conclusion

• ​Computers composed of logic circuits

• ​Basic Logic gates: NOT, AND, OR

• ​Truth table