The document discusses the applications of microprocessors. It explains that microprocessors are used as the central processing unit in microcomputers to perform computing tasks and make decisions. Microprocessors are commonly used in embedded systems and reactive systems to control external hardware and events in applications like consumer electronics, home appliances, automotive systems, medical instrumentation, industrial automation, communication devices, and more. The document provides examples of microprocessors being used for functions like speed control of motors, traffic light control, instrument measurement, appliance operation, building automation, and other control systems.