LED Series Christmas Lights

Leave it alone. The forward voltage drop on white or blue LEDs is higher than red or green, so that's why they chose 35 LEDs per string. If you get too close to the actual line voltage and use lower resistance, any spike will cause a high current surge through the string. If you aren't capable and willing to design and build a constant current boost supply, you are wasting your time.

my guess is the string won't even light up with 70 LEDs in series. Messing with that resistor will probably make the thing an even bigger fire hazard than it is now. If you really want a long string of lights, just add an extra wire the length of the first one to power the second and have the use a common return line. Old zip lamp cord or speaker wire works nice for stuff like this.

The separate sets have an outlet at the far end, so easy to put together. My posting was just curiosity.

Back in 1944, when I was only 8 years old, my grandmother took me to Macy's in New York City to buy me a Christmas present. She was horrifed that the only present I wanted was a string of Christmas lights so I could play with the bulbs and wires. First inkling I was destined to become an electgrical engineer.

Fast forward to 1957, when I graduated from college with a EE degree and got a job at Bell Laboratories. I had a dream job designing switching system interconnect circuits, but also enjoyed playing with Christmas lights.

Really fast forward to 2011, I still enjoy playing with Christmas lights.

Good point about surge limiting, altho I am not sure if LEDs are any more susceptible than tungsten filament lamps.

My first indication of the same affliction was shoving my fingers into the wall outlet. I assume the resultant shock didn't cause any lasting harm, but I'm not sure. My logic was that anything that powerful was worth learning. It's been downhill since then.

When I graduated from college in approximately 1971, aerospace and the space program had just collapsed. I ended up with a job installing radios in cement mixers. No flashing lights or electrocution devices at the time.

It's almost 2012 and I'm going broke fixing electronics and giving away free advice on Usenet. So, I'm slowly switching back to fixing sewing machines. (I was my fathers ace mechanic when he owned a factory in the L.A. garment district). No flashing lights, but plenty opportunity to do damage.

I do like Christmas lights, but they only last until the squirrels are done chewing on the wires.

Tungsten has a time constant, and the resistance goes up as the voltage increases. LEDs are current operated at a lot more constant voltage. A few volt rise in the power line rasies the current flow. Harmonics and spikes on the power line will cause higher peak current flow in the LEDs. It would be like operating a Zener very close to it's knee voltage with only a very low resistance to limit the current.

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The variation in atom size in III-V semiconductors creates more defects than a homogeneous semiconductor like silicon would have, because of the strained lattice. High currents will propagate those defects, creating areas where the steady-state current will bypass the p-n junctions (so-called dark current, because it doesn't produce light). So the useful life of the LED string would be unnecessarily reduced.

"Done", as in "thoroughly cooked"?

It would break your mother's heart if she knew you liked Christmas lights.

When I was 13 I reasoned that if you got a whole bunch of extension cords and plugged them into various different outlets in the house, then wired them all in series you could achieve infinite possibilities. That was only topped by the 120.0 V to 6.0 volt step down transformer I tried to wind on the metal frame of my bed. The schematic showed 8 turns on the primary and 2 on the secondary. Couldn't figure out why I lit up he room.....Lenny

I use solar powered LED lights. Besides using less power, it's more ecologically correct by not electrocuting the squirrels. I leave the lights in place all year to light up the stairs and balcony, leaving plenty of opportunities for the squirrels to ruin my day. One string has perhaps 10 splices. The squirrels are cute, but they're rather destructive.

Nope. Hannukah is the Festival of Lights. The story of Esther specifies using oil lamps, which is proscribed in the local fire code. So, we use electric lights. As long as the lights looked something like a menorah, my parents were satisfied. However, they drew the line with the Hannukah bush. I wanted to also celebrate Christmas, but when they told me that Hannukah was 8 days, and that I was suppose to get one present per day, I decided I could live without Christmas. Unfortunately, the added presents were fairly tacky:

Lesson learned: Next time, get it in writing.

Hannukah also created another area of contention over playing the dreidel.

Basically, it was gambling, which my parents tended to discourage but tolerated because it taught useful skills (math, statistics, probability, bookkeeping, loans, etc). Us kids were soon bored with the dreidel, and switched to playing craps with dice. It was many years before I could understand why the dreidel was acceptable, but the dice were not.

At some point, when I was about 15, I morphed into a very junior Beatnick.

Glorified poverty and a minimalist lifestyle meant that I was required to discard all the trappings of affluence, reject all modern conveniences, drop out of society, avoid clean clothes, and read poetry, thus somehow demonstrating that I was a non-conformist. My parents interpreted that as a rebellion, which they celebrated by cutting off my allowance, demanding that I wash the dishes, and refusing to supply the ritualistic gifts on the usual occassions. This made life intolerable, so I ran away from home. I eventually returned, somewhat wiser, just in time for Hannukah. After receiving the requisit lecture, I was welcomed with a peace offering gift, which I gratefully accepted, thus ending my life as a non-conformist. The lights of Hannukah will always remind me of my first major screwup.

Happy Holidaze.

My son asked me, as a joke, if I could buy him a 5 trillion dollar Zibabwean bill from eBay. I thought he was serious, so in the grand tradition of Chanuka Gelt, he got 5 trillion dollars yesterday. :-)

It's made quite a splash in the humor section of redit.

Geoff.

I see rodent-related threads hereabouts from time to time. The solution has been know for eons. That is the proper seeds in birdfeeders and the proper vegetable extract applied to other things:

A what? Digging....

Plenty of others. Great idea for Hannukah. I wish you had mentioned it a few weeks ago so I could have used it on the spoiled brats.

My father used Hannukah gelt to introduce me to how money works. I think I was 6 years old at the time. He gave me an old silver dollar, and informed me that it was worth more than a dollar. Huh? This was new to me. Explanations were useless, but I kept the dollar well hidden, looking occasionally to see if it would grow. By about 10 years old, I was the only kid in skool with a (co-signed) bank account. I was buying stock when I was 16. The lessons were invaluable.

There are lots of lessons that should be applied or demonstrated early. That includes how to repair things. My father was always fixing things around the house or delivered by friends. Repaired presents were common. I just assumed that he enjoyed fixing things. Later, I found out that he only repaired things because we were sufficiently broke to not be able to afford new items. However, it was too late. By then, I was fixing (well, attempting to fix) things and was hooked.

These days, repair work has changed. In the bad old days, it was assumed that most items worth repairing were of decent quality. These days, I can't just repair things. I have to re-engineer the design and try to improve on what I consider to be crappy design and shoddy construction. In the past, products were usually designed to be maintained. These days, they're designed to be non-repairable. Actually, it's not repair as much as it is remanufacture. In some product areas, it's impossible to buy quality at any price.

Ok. That's my holiday rant.

Interesting idea, but I don't think it will work in the deep dark forest. Chili peppers require a warm climate, dry acidic soil, and plenty of sun. Where I live, only the acidic soil is available. Also, I don't think it will be practical installing chili planters along the hand rails and roof edge, where the Christmas lamps live.

As long as you can get them back into a nice string instead of a bundled ball!

I use corrogated (sp?) cardboard , about 12" tall and 5" wide, with an hourglass waist so the 5" is only 3" wide and wrap them around that. I make sure to roll them up, not twirl them up, so that they don't rotate the remaining string as I wind them on. Works great getting them back off except on those strings that have little ears on the sockets for the anchor-style bulbs, or those mesh style sockets where there are two ears used to make the mesh netting effect. Oh well, if that's the worst thing in life, I have it pretty easy. There are some advantagers to getting old and being retired so I have time to play with these things.

Where are teh sweatshops?

I remember when South of Market was the garment district of San Francisco, but I don't think Esprit and Gunne Saxe, etc., are still sewn there.

Much to my surprise, the venerable Union Special Machine Co is still in existence -- although as a division of Juki -- making mostly specialty machines for such applications as bags and Astroturf.

Alive and well in China and Vietnam.

We sold the biz shortly after my father had a stroke in 1986. At the time, the downtown area of Smog Angeles was in the process of morphing into a disaster area. Reputable businesses and stores were moving out, to be replaced by importers, discounters, and empty factories.

Very little of what's being sold was made locally.

Many garment manufacturers were purchased and had the entire factory shipped overseas. Most of the garment production initially went to Korea, which was also the main source of synthetic material. It then shifted to Viet Nam where there are still large factories. Viet Nam couldn't handle the huge growth in low cost clothes, so much of the business went to China. Some also went to Mexican maquiladoras, but nothing compared to the volume in China.

New York isn't doing any better than Smog Angeles:

In the garment biz, most items require a specialty attachment in order to be efficient. You start with a basic machine, and then add attachments, fixtures, and automation, all of which are highly customized. The average lifetime of a style or pattern does not lend itself to dedicated machines.

ty

So, were you just joking, or are you planning to move to China?