A PA system, or Public Address system, is a set of equipment used to amplify sound so that it can be heard by a large audience. It typically includes microphones, amplifiers, loudspeakers, and sometimes mixing consoles. PA systems are commonly used in various settings, such as schools, concerts, and public events, to ensure clear communication. These systems can vary in size and complexity, from small portable setups to large installations in stadiums. They help deliver announcements, music, or speeches, making it easier for people to hear important information in crowded or noisy environments.