Christmas light strings have to be plugged into an outlet as a source of electricity to power the lights. Some Christmas lights can be bright, but you can dim the lights on your Christmas tree or in other areas of your home by plugging the light string into a dimmer device, which can be purchased at lighting stores, home improvement stores and many department stores. The dimmer plug-in allows you to control the brightness level of your Christmas lights.
Purchase a light dimmer plug-in. Check that the plug-in you are purchasing matches the two-prong or three-prong design of the Christmas lights you will be plugging into the dimmer. Also, check to see how the dimmer works—whether it is a switch or a sliding mechanism that allows you control the brightness of the lights. You should buy a dimming plug-in device for each of the light strings you want to dim.
Plug the dimming device into the electric outlet near the area of the Christmas lights.
Plug the Christmas lights into the dimmer device.
Move the dimmer switch to change the brightness level of the Christmas lights. Switch or slide the control to adjust the brightness of the Christmas lights that are plugged into the device.
If you have a dimmer switch installed on the lights in your home, you may be able to use the installed dimmer switch to control your Christmas lights. This will only work if the light fixture in your home is plugged into an outlet and this is how you control dimming or brightening the installed lights. If this is the case, then you can unplug the light fixture in your home that is connected to the dimmer switch and plug in the Christmas lights to the outlet from which you unplugged the light fixture. Once you do this, you will be able to control the Christmas lights with the dimmer switch.
Some dimmer plug-in devices have more than one plug receptor, which means that you can plug more than one strand of Christmas lights into one device.
To control the dimming of more Christmas light strands at a time, plug the strands of Christmas lights into each other and then plug the end of the long Christmas light strand into the dimming device.