What is an H-bridge and what are the applications of an H-bridge?
The direction of current flow through any device can be changed using H-bridge. It is useful for driving motors and controlling their direction. For example in a remote control car, the direction of wheel’s rotation can be either clockwise or anti-clockwise (based on forward/backward movement). This change of the wheel’s direction is controllable with the help of h-bridge. Figure (wheel direction)
Components Needed For H-bridge Design
4 x MOSFET IRF Z44N
2 x LED
2 x Push buttons
1 x DC Motor
2 x 10K Ohm Resistor
2 x 470 Ohm Resistor
1 x Breadboard / Veroboard
Simulation on Proteus
It is recommended to simulate this design on Proteus before proceeding towards hardware development. The design can be altered schematic design according to your requirements and verify its functionality on Proteus.
Proteus is easy to use and if you are using it for the first time, you can download Proteus from this link and learn how to use Proteus from VerifiedSchematics YouTube channel.
How does a MOSFET IRFZ44 Based H-bridge works?
H-bridge is designed with a combination of transistors, and that’s why the specifications of an h-bridge depend upon the transistors used. Transistors can switch devices with the help of a small signal directed on their base/gate. Usually, four transistors are used in an h-bridge as two pairs. The gate/base of each pair is connected, and any signal passed to their gate/base switches transistors and accordingly the flow of current is determined.
For examples, If Push button B is pressed, the gate pins of transistor Q1 and Q2 are signaled, the DC motor rotates in clockwise direction.
While if the gate pins of transistor Q2 and Q3 are signaled, the DC motor rotates in the anti-clockwise direction.
The push buttons used in this verified schematic are to pass a High (+5v) signal to transistor’s gate/base. The 10K Ohm resistor (connected with the push from one end and grounded on the other end) is to keep gate/base signal LOW (0v) when no signal is passed. This is necessary to avoid unexpected behavior of transistor due to noise. Transistors are very sensitive to voltage signals. Transistors can switch even if their gate/base is slightly touched with fingers.