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 or mood-enhancing environment. Dimmer switches can be used with various types of lighting, including incandescent, LED, and fluorescent bulbs. These switches work by varying the amount of electrical current that flows to the light. Some dimmers use a simple rotary knob, while others may have sliders or touch controls. Installing a dimmer switch can also help save energy and extend the lifespan of your light bulbs.