

Are Christmas Lights in Series or Parallel? - dnetesn
http://www.wired.com/2014/12/christmas-lights-series-parallel/

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cpwright
Unfortunately, the bypass wire doesn't actually always burn out to make the
rest of the lights work. There is a device called a LightKeeper pro that sends
a larger "zap" through the string to encourage the needed bypass wire to burn
out. Its saved me a bunch of time figuring out which bulb was bad in a string
of lights.

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fbe
Or you can also DIY with a lighter : [https://www.youtube.com/watch?v=7foDiXX-
CcE](https://www.youtube.com/watch?v=7foDiXX-CcE)

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vortico
tl;dr Christmas light bulbs each have a bypass wire which is initially
insulated to avoid shorting the filament. If the filament burns out, the new
high electric potential burns off the insulation, thus re-completing the
circuit for the rest of the bulbs.

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shreyas056
Actually this is what I hate about such articles, they extrapolate two
sentence explanation into huge corpus.

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Rapzid
I understand the article is about series vs parallel but I'm sort of... Taken
aback by the premise setup in the beginning that:

A.) Its hard to find the burnt out bulb(hint its almost always the one with
the broken filiment)

B.) You should just throw the strand away

Maybe I'm just too old at 30(?) or I grew up underprivileged because I recall
untangling lights and replacing burnt out bulbs well, as far back as I can
recall. 7 or so? And throwing the strand away is just wasteful.

I understand there is an article to write but on one hand we have some guy
writing about creating a sou-vide oven and on the other someone suggesting
burnt out light bulbs are too hard to find. :|

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icebraining
I agree with you, and I also replaced burnt bulbs as a kid, but nowadays I'm
seeing more and more Christmas lights using molded plastic instead of sockets
(also, usually with LEDs instead of bulbs), so replacing them is much harder
than it used to be.

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_mulder_
True, but you shouldn't need to replace an LED bulb like you did the
incandescent's. More likely to be a problem with the transformer or cheap wire
and connections.

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userbinator
A truly appropriate article for a site whose name is "wired".

LED sets are usually wired in series too, since they're current-driven
devices.

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tmuir
Although most LED matrices have parallel columns of series LEDs, since they
are usually multiplexed at high speed to create the persistence of vision
effect.

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mbell
The answer to this, at least for longer strings, is usually 'both'. You'll
usually find several sets of series wired runs connected in parallel and
sometimes mid run branches.

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Animats
The price ratio between comparable LED and incandescent holiday light strings
is now between 2 and 2.5 to 1. Incandescent holiday lights probably have about
two to three years of life left as a product.

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bradfa
The white LED strings look very nice and I definitely agree that white
incandescent strings have a very short market life left. But the colored LED
strings which are sold at Home Depot and similar merchants in the USA have
very different colors than the incandescent strings.

I personally find the colored LED strings to have very unpleasing colors
compared to incandescents. I've tried a few different "brands" (in quotes as
the brand is mostly meaningless afaict) of LED strings and all were not to my
liking.

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funion
Oh interesting, I'd noticed that at some point between my childhood and now,
burned out bulbs stopped taking out the entire rest of the light string. I
wonder if the bypass wire is a new(ish) development, or if we just had cheap
Christmas lights when I was younger.

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virmundi
You had cheap Christmas lights. We had both. We had the actual bubble lights.
Those were more expensive at the time. A bulb could burn out in one of the
bubblers and the remaining bubblers would work.

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raldi
So why aren't the bulbs hooked up in parallel?

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chillacy
Probably to save wire, if you hooked em up in parallel you'd need to send a
wire to every bulb from the outlet.

With 10 bulbs at 1 inch spacing, you're wiring 1 + 2 + 3 + ... + 9 + 10 = 55
inches of wire instead of 10

Follows a roughly N^2 law

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vonmoltke
It requires 20 inches of wire in both cases. When connected in parallel, each
socket acts as a pass-through to connect the hot and grounded wires to the
next socket in the set, in addition to providing power to the bulb. Thus, the
_sockets_ are in series but the _bulbs_ are in parallel. This is how
electrical wall outlets are wired.

The problem is that a parallel connection requires bulbs that can take 120VAC
directly. This is not a problem with C7 and C9 light sets (the small Edison
base bulbs). The minis, though, can only take a few volts. Thus, they need to
be series-connected to get the voltage drops across the individual bulbs to
the level a single bulb can handle.

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Sharlin
Or you could use a transformer.

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vonmoltke
Sure, and some sets did. It doubles the cost of a basic light set, though, so
they were usually only found in the higher-end sets.

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francis88
Curious to know what would happen if 2 or more bulbs broke at the same time?

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guidedlight
In Engineering, there is no such thing as "at the same time" unless it's a
feature of the design.

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swah
I thought those christmas lights had bee replaced by led strips.

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mindslight
Piercing blue, icy white, and unfocusing violet aren't so inviting on a cold
winter's night.

Black body 4 life.

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copperx
What's the problem with coloring the lens?

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sokoloff
LEDs emit a limited number of wavelengths of light.

Incandescent lamps emit a broad spectrum of light.

Filters (colored lens) can knock out certain colors, allowing others to pass.
Filters cannot add colors that aren't there to begin with.

You can't just filter a monochromatic light into another color. Filtering LEDs
doesn't work as straightforwardly as your incandescent-based intuition would
lead you to believe.

