A power source is a device or system that provides energy to operate machines, tools, or electronic devices. Common examples include batteries, generators, and electrical outlets. These sources convert different forms of energy, such as chemical, mechanical, or solar, into electrical energy that can be used to power various applications. Power sources are essential in everyday life, as they enable the functioning of appliances like refrigerators, computers, and lights. Understanding how different power sources work helps in choosing the right one for specific needs, ensuring efficiency and reliability in energy use.