# Christmas Lights......

Discussion in 'General Electronics Chat' started by steev, Jun 20, 2011.

1. ### steev Thread Starter New Member

Jun 12, 2011
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Hi All,
Got a simple question, but I can't answer it myself because as I write I'm on a ship in the middle of the ocean...
Christmas lights..... can anyone remember what's usually printed on the box regarding the elctrical requirements eg, 110v, 5ma, resistance etc etc.
(those figures are wrong, they're there just an example!!!).

I'm a beginner at learning and thought a fun and easy project would be to rewire a broken string of lights into shorter sets, perhaps buy an adaptor. And as I sit here in the middle of nowhere, I'm just thinking through what/how/best way to do it.

Thanks,
Steve

2. ### ErnieM AAC Fanatic!

Apr 24, 2011
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1,623
Well... it depends! A string of lights can have several substrings of various lengths. As I remember they are either 32 or 50 lights per string, and each string is in series and the string goes across the AC line. So the individual bulbs are either 120/32 or 120/50 volts each.

I think it would be more fun to ponder why a burned out light has a lower resistance then a working light. Yep, when they burn out they are made to short themselves, but how they do that is an interesting puzzle!

Apr 30, 2011
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They have a resistance wire in parallel with the filament that is slightly higher than the cold filament resistance.

The better miniature bulbs run 6V each so a set of 100 has 5 strings of 20.

4. ### Wendy Moderator

Mar 24, 2008
20,772
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Nowdays Christmas lights are LEDs. Most of the ones I've seen would not pass muster with our TOS, ever (even before the new TOS was released). To put it simply, many commercial models are not really safe. Over time I expect this to shack out, but the UL and other regulatory bodies have not quite caught up with reality.

The variation out there is huge though, so there is no telling what kind the OP is talking about.

5. ### steev Thread Starter New Member

Jun 12, 2011
6
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The ones I'm talking about are those boxes we buy in Hobby Lobby or somewhere - 150 lights in 3 sets of 50 "one burns out they all stay lit".
I thought it would be a fun and easy project so that when one light burns out I only have, say, 10 lights in a series, that stop, instead of 50.
Ultimately, my plan is to perhaps rewire them into shorter series so that instead of 3 sets of 50 I may have something like 10 sets of 15, or 15 sets of 10, or 30 sets of 5 .......
Maybe it's a silly "learning" project anyway.........?

Regards,
Steve