Why are strings of Christmas lights so unreliable? Why aren’t strands made so that a single light can go out and the rest stay on no problem?
In: Engineering
It’s actually a bit tricky to do with a string that has the LEDs or light bulbs wired in series.
One broken light will interrupt the power to all others, so if you want the string to continue working, you need to provide a path for the current to flow despite the broken light. A bypass basically.
The problem is that when there’s a bypass in place, the electricity would simply take the path of least resistance (through the bypass) and the light wouldn’t illuminate, even though it’s still working. So you need a special kind of bypass that only works when the bulb is broken. There’s a special type of diode called Zener diode which can be used to do that, but that obviously adds cost and makes the string more complicated to manufacture.
The other solution would be to wire the lights in parallel, but that’s not a great solution for LED strings since it can result in uneven brightness, and it’s more costly because a parallel circuit requires two wires instead of just one.
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