A PID controller is a type of feedback control system widely used in industrial automation. The acronym "PID" stands for Proportional, Integral, and Derivative, which are the three components that work together to maintain a desired output. The proportional part responds to the current error, the integral part addresses past errors, and the derivative part predicts future errors, allowing for smoother control. These controllers are essential in various applications, such as temperature regulation, speed control, and pressure management. By continuously adjusting the control input based on the error, PID controllers help systems achieve stability and improve performance, making them a fundamental tool in engineering and technology.