Lights on! It’s Christmas time
The lighting used, as you might have noticed, is key to the decorations. Traditionally, wax candles were used since the 17th century to decorate the tree.
Christmas lights these days either employ incandescent lamps or LED lights, which is growing in popularity. While most of the initial models came in series connection, wherein the failure of one lamp meant that the entire lighting failed, models these days are available both in series and parallel connections.