Hey Learners! Welcome to The Engineering Projects. We hope you are doing great. Our team is working on transistors and today, we'll design a circuit for using the 2N2222 Transistor. In this chapter you will learn:
1. What is H Bridge with 2N2222 Transistor?
2. How do the 2N2222 Transistor works?
3. What is the working of H Bridge?
4. How can we run the circuit of  H Bridge in Proteus using 2N2222 Transistor?
By the same token, you will also learn important information about the topic in DID YOU KNOW Sections.

Introduction to H-Bridge

In electronic circuits, the direction of quantities like the flow of current, EMF, Electric field lines matter a lot. The H Bridge is used to control such motors through its specialized circuitry. The H Bridge is defined as:
"The H Bridge is an elementary circuit that ends the Motors to rotate in forward or backward direction according to the will of the user."
In this way, there is no need for the two motors in many cases. Only one motor can be used to accomplish the task instead of two.

DID YOU KNOW???

The most common, easy and interesting application of the H Bridge is in the robotics. The H Bridge is used to run the motors of the robots that are required to move the robot in the forward and backward direction.
The circuit of the 2N2222 H Bridge allows the current from the Direct Current source to flow from the required direction only and hinders the flow from the other direction.

Why we need the H Bridge

The direction of the moving of a motor paly a vital role in the output of that motor. The reason behind this is, most electric motors operate due to torque produced as the combined effect of magnetic field and electric current through a wire winding. Hence, We always need some means through which we can control the direction of the Motor to get the output that is suitable for our present requirement.

Performance of 2N2222 Transistor in H Bridge

The 2N2222 Transistor works as a backbone in the circuit of the H Bridge. We use four 2N2222 Transistors in the circuit and they work as a couple. The diagonal Transistors work together as a couple and allow the flow of current through them. By the same token, the non-diagonal 2N2222 Transistors work as a couple. Let's have a look at what is 2N2222 Transistor:
"The 2N2222 Transistor is a type of Bipolar Junction Transistors or BJTs that is designed to be used in the low power amplifying or switching applications."

DID YO KNOW???

Motorola made many semiconductor companies and the 2N2222 is  part of a huge family of Devices and Transistors that were discussed in IRE Conventions in Motorola company.
Being a BJT Transistor, the 2N2222 allows the flow of current in only one direction. Thus, it is responsible for the rotation of the Motor as per requirement of the user. The 2N2222 transistor (just as other JTs) has three pins. These pins are called Emitter, Base and Collector. The arrow symbol just at the transistor symbolizes the Emitter. Being an NPN Transistor, the collector and emitter terminals of 2N2222 Transistor in H Bridge act reverse biased or are said to be left open when the base pin is held to the ground or when there is no current flow from the base. On the other hand, when the base gets the flow of current from the battery or other components of the circuit in the H Bridge, the circuit is said to be forward-biased. The gain of the 2N2222 Transistor in the H Bridge ranges from 110 to 800. The value of gain is responsible for the determination of the 2N2222 Transistor's amplification capacity in the H Bridge.

Working of H Bridge Circuit

When we look at the circuit of H Bridge we get the following points:
1. The Direct Current from the battery originates from the positive terminal of the battery (considering the conventional current) and passes through the switch.
1. The switch allows the current to pass through the pair of the 2N2222 Transistor that is to be used.
2. The resistors just before the Transistors perform the regulation of the current through the transistors.
3. In our case, the H Bridge works according to the table given below:
 Switch Flow of Current Direction of Motor Connected to A From T4 to Motor then Motor to T1 Anti-Clockwise Connected to B From T2 to Motor then Motor to T3 ClockWise
Let's have a look at the working of the H Bridge in action in Proteus ISIS.

Circuit of H Bridge in Proteus ISIS

We are going to design the circuit of the H Bridge in the Proteus ISIS. But before this, let's have a look at the required devices for the circuit.

Required Devices for H Bridge

1. 2N2222 Transistor
2. Resistor
3. Motor
4. Cell
5. Switch
6. Connecting Wires
Now,  just follow these simple steps:
• Click at the "P" button and choose the required devices except for connecting wires one by one.
• Arrange for 2N2222 Transistors, four Resistors, motor, switch and cell on the working area.
• Change the orientation of two of these Transistors before setting on the screen by clicking the arrow sign given just above the "P" button.
• Left Click the motor>Rotate clock-wise to change the direction of the motor according to the image given next:
• Change the value of Cell and Motor to 6v by double taping them one after the other.
• Connect all the components according to the circuit given next:
• Double click at all the resistors and transistors one after the other and label them to identify them as different devices.
• Pop the simulation button.
• Change the orientation of switch and check the output.