how to find the bad bulb in christmas lights

There are a few ways to find the bad bulb in Christmas lights. One method is to check the fuse in the plug to see if it has blown. If the fuse is intact, you can use a multimeter to test the resistance of each bulb. A bad bulb will have a higher resistance than a good one. Alternatively, you can use a voltage tester to check for continuity between the wires at each bulb. A bad bulb will not have continuity, while a good one will.