A dimmer switch is a device that allows you to adjust the brightness of a light fixture. Instead of just turning the light on or off, a dimmer lets you set the desired level of illumination, creating a more comfortable and customizable lighting environment. They can be used with various types of bulbs, including incandescent, LED, and CFL. Dimmer switches can enhance the ambiance of a room, making it suitable for different activities, such as reading or entertaining. They are also energy-efficient, as reducing the brightness can lead to lower electricity consumption, extending the lifespan of the bulbs used.