to reduce the current supplied to each LED. Neon-lamp-based sets have lamps connected in parallel, each with its own current-limiting resistor. Battery-powered sets are also wired in parallel. Some incandescent or LED-based strings use a power supply transformer with lamps connected in parallel. These sets are much safer, but there is a voltage drop at the end of the string causing reduced brightness of the lamps at the end of the set. The reduced brightness is, however, less noticeable with LED-based sets than incandescent sets. Power supplies with integrated plugs may make the set difficult to connect in certain places. A line-operated AC string with a male plug on one end and a female socket on the other end can be conveniently connected end-to-end with other similar strings. The gauge of wire used, current rating of the fuse (if present) and the power consumption of each string will determine how many strings can be safely daisy-chained this way, or whether the end string will have diminished voltage and brightness. Safety The number of strands of continuous light sets that may be safely daisy-chained in sequence varies based on whether the lights are LEDs, ordinary miniature light bulbs, or the larger C7/C9 type light bulbs. Other factors include the voltage of the set and the size of the wiring in the set. Those with questions should consult the manufacturer's instructions or an electrician. Most light sets come with built in fuses to help protect against overheating and to prevent household fuses or circuit breakers from being tripped. If a fuse blows, the strand must be unplugged and the number of strands must be reduced. If the strand has nothing attached, or has blown repeatedly, it may contain a short circuit and should be repaired or discarded. An episode of the Discovery Channel television show MythBusters covered the possible fire danger from holiday lights. References Christmas traditions Lighting