Metal–Oxide–Semiconductor Field-Effect Transistor is a transistor used for amplifying or switching electronic signals. We use it in our computers, telephones, game consoles, cars, electrical appliances and in this case, our amplifiers. They are found in systems where information is processed or stored. A MOSFET is basically an electrical switch that allows the flow of electrical current. An electrical switch has two possible states, on and off. This is where the MOSFET performs its most important role in our D Class amplifiers by allowing or preventing the flow of power and creating an efficient amplifier. The “Pulse Width Modulated” is a design that is significantly simplifies power supplies. It controls the output voltage and current precisely by not only removing the output current sensing loss, but also eliminating all secondary feedback circuitry. The PWM can increase efficiency, is lighter, smaller, can reduce total cost, productivity and system reliability.