A dimmer switch is a device that allows you to adjust the brightness of a light fixture. By changing the voltage supplied to the light bulb, it can create a range of lighting levels, from bright to soft. This feature is useful for setting the mood in a room or saving energy. Dimmer switches can be installed in place of standard light switches and are compatible with various types of bulbs, including incandescent, LED, and CFL. They come in different styles and designs, making it easy to find one that fits your home decor.