## Introduction: AND OR NOT !! (interactive Thruth Table)

Hey guys , I hope you all are well at your home and wondering what to tinker out of the available materials ??

Understanding logic gates is very important for both the electronics student and as well as a computer science student , unfortunately there are very few practical experiments(raw logic gate) that you can experiment on the logic gates !!?? So,for this reason let's build one from scratch and also most of the component can be recycled from old electronic circuit !!

NOTE: I will not be using a transistor , so don't run away , it is fairly simple to do.Anyone with basic electronics knowledge can build the circuit in hours !! If you have trouble in understanding this , do check out the video !!!

## Supplies

The main component of the circuits are :

• DIODES(IN4007) x5
• Jumper Switches x5 (as I mentioned earlier it can be recycled , also you can use any switch of your choice)
• LED's x3
• Coin cell holder and 3V cell / 9V battery clips(if you use 9V battery remember to use a resistor also(1k ohm , should do good))
• Breadboard / Prototyping Board / Breakout Board (choice is yours)
• Soldering Equipment

## Step 1: Little Bit of Theory

### What is a Logic gate ??

A logic gate is an electronic gizmo that returns a boolean value(like true or false) based on the given conditions or the value !!

Note that a typical Logic Gate returns only single output !!

### Why do we use a logic gate !!??

A logic gate is the fundamental form of a micro controller or more precisely the decision making tree !! Which is a cool programming concept (like if-else statements). So an output can be triggered based on several conditions , this opens a whole new concepts such as encoders,decoders,subtractors , comparators and much more !! In a real world example this logic gates can be similar to the yes or no trivial questions !!

## Step 2: Building the AND Gate

### AND gate :To build the AND gate :

we will be needing a power source,x2 diodes,x2 switches which serves as the input and a LED to indicate the output !!

[NOTE : you can also build this on breadboard for your comfort]

### This is how the circuit was built:

It is a common forward biased diode that is connected with a switch at one of it's terminal and a LED on the other terminal!! Next the second diode is attached in reverse biased with respect to the LED and also a second switch is attached in between the power source or the LED connection !!

Don't worry refer the circuit diagram you will understand !!

### How it works !!

When the forward biased is toggled on or practically is in HIGH state the diode will be in forward biased and then lit up the LED while it's in LOW state the diode has infinite resistance and thus doesn't conduct !!
This simple it is !!

It is a basic gate that applies the logical AND operation on the given binary input, practically the AND gate can be ON if both the logical input is HIGH and OFF if either one of the input is LOW !!

### Real Life Examples are :

Deciding weather to attend the college or join a friend's party !! You can't be at both the place at a given time !!

## Step 3: Building OR Gate

### To build the OR Gate:

We will need a power source,x2 diodes,x2 switches which serves as the input and a LED to indicate the output !!

### How the circuit was built :

At first the 2 diodes are connected in common to the +ve source later each end of the diode is connected with a switch and later the LED is connected !!

Don't worry refer the circuit diagram you will understand !!

### How it works:

When the forward biased is toggled on or practically it is in HIGH state the diode will be in forward biased and then lits up the LED , while it's in LOW state the diode has infinite resistance and thus doesn't conduct !!
Since the current flows in it's respective paths , the circuit can be toggled ON individually!!

An OR gate is fairly simple logic gate performing logical Or operation and remains ON if either of the inputs are HIGH and remains off if both the INPUTS are LOW !!

### Real Life Example :

When you are deciding what to eat over the brunch weather to have a pizza or burger !! But you can also have both at a time !!

## Step 4: Finally the NOT Gate

### To build a NOT Gate:

We will be need a power source , diode , LED as an output and a switch as an INPUT !

### How the circuit is built :

Firstly we start connecting the diode in forward biased with the LED connected in far end of the terminal later a switch is introduced between the -ve terminal of the Diode and +ve terminal of the LED , this way we are creating a backtrack to the Ground this way you are not short circuiting and thus prevents unwanted power loss!!

Don't worry refer the circuit diagram you will understand !!

### How it works :

When the circuit is in LOW state meaning the switch is not toggled on(HIGH STATE) ,the circuit is still able to conduct , because there is no intervention between the path!! But when the circuit is in HIGH state that is the switch is toggled on(HIGH state) then there creates a backtrack to the ground which simply diverges the current that is flowing into the LED is now flowing towards the ground in a new channel, thereby the LED is not lit !!