A dimmer is a device used to adjust the brightness of a light fixture. It works by varying the amount of electrical power that reaches the light bulb, allowing users to create the desired level of illumination. Dimmers can be found in various forms, including wall-mounted switches and remote-controlled units, and are compatible with different types of bulbs, such as incandescent, LED, and CFL. Using dimmers can enhance the ambiance of a room, making it suitable for different activities, from reading to entertaining. They also contribute to energy savings, as lower brightness levels consume less electricity. Additionally, dimmers can extend the lifespan of light bulbs by reducing the amount of power they use.