Registered: Jan 2003
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SOAK: Pre-lit fake Christmas trees.

Wife and I were shopping for a fake Christmas tree. As you may know, some come with the lights already in place.

So she asks me, "You're the engineer, what happens if a bulb goes dead in one of these pre-lit Christmas trees, does it make the entire tree go dark?"



I told her I was sick that day in college.

Anyone know?

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Registered: Feb 2002
Location: 19th hole
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The lights on those trees are usually wired in parallel, not series, so the rest of the tree stays lit.

Think of parallel wiring as being like a railroad track with the lights being on the ties, so if one light goes out, the rest will stay lit. In series wiring there's one continuous wire that goes into a light, out, into the next light, so if one light burns out, the whole string goes.

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Registered: Sep 2001
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Then again, the really cool ones use fiber optics and has a single really bright light in the base. With that there is only one bulb to burn out.

-Mike

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quote:

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Originally posted by gregpr
The lights on those trees are usually wired in parallel, not series, so the rest of the tree stays lit.

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Registered: Jan 2002
Location: Berkeley CA
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How fire-resistant are these pre-lit trees?

Jan

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Registered: Dec 2001
Location: Alabama
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I'm not sure how fire-resistant they are. They are pretty much the standard artificial tree.

We've had a pre-lit 12' tree for the past 2 years. Setting it up is a breeze. We've not had any lights to burn out yet. I'm sure this year will be the year.

It has mega-lights on it. They are very pretty.

Before we had the pre-lit tree, we wrapped the strands of lights around *each* branch, rather than just draping them around the tree in a circle. The effect was stunning. The tree seemed to glow from within.

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Registered: Jul 2003
Location: Arlington Heights, IL
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Are you sure they just don't set it on fire on your way out of the store for you. Would probably be a hectic ride home, with a tree on fire and all. Just think if someone parked in front of you and your reverse didn't work and the tree is on fire and....well you get the picture.

rberry88

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Normal Christmas tree lights are are low volatage and wired in series to divide the 110V down. Big sets may have more than one string of series bulbs.

So you would expect that if one bulb blows then they all go dead?

The trick is that each bulb (except for the fuse bulb) has a filiment and a bit of resistance wire in parallel. When the filiment burns out the resistance wire is still connected, all be it that now the bulb has a higher resistance.

This means slightly less current circuit and slightly higher drop across the bulb so all the other bulbs will get slightly dimer but you won't even notice.

Nick

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quote:

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Originally posted by jafa
Normal Christmas tree lights are are low volatage and wired in series to divide the 110V down. Big sets may have more than one string of series bulbs.

So you would expect that if one bulb blows then they all go dead?

The trick is that each bulb (except for the fuse bulb) has a filiment and a bit of resistance wire in parallel. When the filiment burns out the resistance wire is still connected, all be it that now the bulb has a higher resistance.

This means slightly less current circuit and slightly higher drop across the bulb so all the other bulbs will get slightly dimer but you won't even notice.

Nick

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Registered: Sep 2003
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We bought an awesome pre-lit tree from Wal-Mart last year. Love it.

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quote:

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Originally posted by mrs-j
We bought an awesome pre-lit tree from Wal-Mart last year. Love it.

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Registered: Sep 2003
Location: Oak Hill, Virginia
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No dead bulbs and very easy to store. Comes apart in 3 sections and each level of branches opens up and then later folds up quite tightly. For the best prices, I can recommend the Wal-Mart trees. Comparable to the ones we found at Lowes and Home Depot and Target, but about $30 less.

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I bought a pre-lit tree at Target last year... in January. Got it for 75% off. I haven't taken it out of the box yet.

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Registered: Jan 2003
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Bought a pre-lit from Target two years ago. It folds out like you describe and fits right back in the box when we put it away. We love it.

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quote:

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Originally posted by will_not55
I assume the parallel R wire is within the base where the bulb goes in.

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Registered: Jan 2002
Location: Fort Myers, FL
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I recently saw a pre-lit that claims that if one bulb burns out the lamp before and behind it will go out too makiing locating the bad bulb very easy.

I'm also in the market for a new tree this year so post sources if you find any deals.

I like what I see here.

http://www.treeclassics.com

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