What is the role of the MOSFET on a hard drive PCB?

The MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) on a hard drive PCB is used to regulate power to the internal components of the hard drive. The MOSFET acts as a switch, allowing or blocking the flow of current to the hard drive's read/write heads, spindle motor, and other components. The MOSFET is controlled by the hard drive's firmware, which adjusts its operation based on the demands of the computer's operating system. The MOSFET is an essential component for the performance and longevity of the hard drive, as it helps to regulate power and prevent damage to the internal components.