Hello Learners! Welcome to

**We are here with a new tutorial. Before this, we learnt about**

*The Engineering Projects.**Basic Logic Gates and Truth Tables in Proteus.*In previous tutorial, we have had a look at NOR as Universal Gate in Proteus ISIS. Today, We’ll perceive about another Logic Gate derived from the Basic Gates.

Recall that* Logic Gates are the pillars of Digital Logic Circuits.* Therefore, it is useful to recognize the fundamental knowledge about Logic Gates.

Today, we’ll seek the answers of the following Questions:

- What is NAND Gate
- How is the Truth table and the timing diagram of NAND Gate.
- What are Universal Gates.
- How NAND is universal Gate
- How can we implement the NAND Gate as Universal gate in Proteus ISIS.

Hence, Lets find out all the answers.

### NAND Gate

As the name implies, NAND gate is the Combination of two Basic Gates i.e AND Gate and NOT Gate. We describe the NAND gate as:

“The Universal Gate that is the Combination of both AND Gate and NOT Gate is called the

NAND Gatethat gives the LOW output only when both its Input are HIGH.”

The output of the NAND Gate is the inverting result of the AND Gate.

Assume that A and B are two inputs f the NAND Gate, then the Output Y is denoted by a dot between the inputs along with a combine compliment or a bar on the whole statement.

**Y= (A.B)’**

For graphical Representation of NAND Gate, we denote the NAND Gate with a small bubble at the end of AND Gate. This Bubble is called the Negation Indicator.

### Truth Table and Timing Diagram of NAND Gate

If we look at the truth table, it is the inverse of AND gate.

A | B | (A.B)’ |

0 | 0 | 1 |

0 | 1 | 0 |

1 | 0 | 0 |

1 | 1 | 0 |

The inversion is due to the NOT Gate’s ability in the NAND gate.

At the same token, when we observe the timing diagram of NAND gate, we get an image given next:

### Universal Gates

In Logic Circuits, we often use a term called “Universal gates”. this can be defined as:

“The category of Logic Gates, through which we can derive all the Basic Gates are called universal Gates.“

We have two Universal Gates, NAND Gate and NOR Gate. These have importance in the world of Digital Logic Designs because of their simplicity and usefulness.

### NAND as a Universal Gate

As discussed before, NAND Gate is a Universal Gate. It is because, when we design carefully the circuit of NAND Gate through some Combinations, we can use the NAND gate to obtain the output as the Basic Logic Gate, Truss , with this single Gate, we can get the output of :

- NAND Gate
- OR Gate
- AND Gate
- NOT Gate

We’ll Explain this procedure just after this section. Let’s Prove the discussion by the mean of Practical Implementation.

## NAND as universal Gate in Proteus ISIS

We can Implement the universal Gates to make the all Basic Gates named as:

AND Gate, OR Gate and NOT Gate.

This will be done in the Proteus ISIS and we’ll describe each of them one after the other.

### Material Required:

- NAND Gate
- Logic Toggle
- Logic Probe
- Connecting Wires

Take the discussed elements from the pick library One after the other through “P” button.

Follow the instructions to make all the Gates one by one.

## Basic Gates through NAND Gate

### OR Gate

While Designing the OR Gate through NOR Gate, we must have the knowledge about one rule of Digital Logic Design that says:

“The Compliment of the ANDed input is equal to the ORed inputs.”

Mathematically,

**(A’B’)’=A+B**

- Take an NAND gate from the library and fix it at the working area.
- Repeat the step two times.
- Connect the output of two NAND Gates with the input of third one.
- Connect the inputs of other two remaining Gate with each other through a wire to set them as one input.
- Connect logic Toggles as the input with two NAND Gates.
- Join Logic Probe to visualize the output.

The circuit looks like this:

- Pop the play button.

### Change the value of inputs one by one and record the output in the form of table.AND Gate

We’ll Design AND Gate through NAND Gate on the basis of the following rule of logic Design:

“The Compliment of ANDed inputs is equal to the ANDed inputs.”

**(A.B)’=A.B**

- Get two NAND Gates from Pick Library.
- Set them at the working area.
- Join then inputs of 2nd Gate with each other.
- Set Logic toggles at the input of the 1st one.
- Join Logic Probe with the output of 2nd one.
- Connect the output of the 1st Gate with the inputs of the other.

- Change the inputs through Logic Gates.
- Record the truth table according to the output.

### NOT Gate

The formation of NOT Gate through NAND Gate is based upon the rule:

“The Compliment ANDed input with itself is equal to the complement of input.”

**(A.A)’=A’**

- Take the NAND Gate.
- Fix it at working area.
- Connect its both inputs with each other.
- Connect Logic Toggle and Logic Probe.

- Change the inputs.

The resultant Truth Table is:

**NOTE: **You can Gain the same output by following the rule (A.1)’=A’

### Advantages of NAND Gate

- NAND Gate is a universal gate therefore it can make the circuit less complex.
- We can use them for the functionality of more than one Gate.
- It stores more storage capacity as compared to its size.
- It is Cost effective per byte.

### Real life Applications of NAND Gate

- Freezer warning buzzers.
- Burglar Alarms.

### Disadvantages of NAND Gate

- It is Difficult to design than other Gates.
- It has propagation delay.
- The high Gate count is also a disadvantage.

Consequently, we recognized the Core detail of NAND gate, we learnt what are the universal gate and how can we make different gates with NAND gate using Proteus simulation. moreover, we got some of the advantages, disadvantage and some real life applications of NAND Gate.