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Post by clarencebunsen on Jan 22, 2015 19:20:04 GMT -5
I killed an LED bulb today, an infant mortality. It had been in use in the overhead fixture in our kitchen for couple months. I decided to try it in the lamp next to our couch in the family room just to see if I liked the color and light distribution pattern before buying a replacement bulb for that lamp. After a couple minutes I stood up and reached to turn it off. As my finger neared the switch there was a static spark and I had a bulb with non light emitting diodes. I may have to rethink my bulb replacement strategy.
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Post by dave on Jan 22, 2015 23:17:18 GMT -5
I tried one set of led bulbs when they first came out. They have hopefully improved, but though I was willing to pay more because they were supposed to "llast ten times longer," mine didn't last very long at all.
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Post by clarencebunsen on Jan 23, 2015 6:27:02 GMT -5
I have a few and that's the only death so far. Of course the technology is changing so fast it's very difficult o run A/B comparisons. By the next time I shop for one the model I bought last time has been replaced.
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Post by kit on Jan 23, 2015 10:04:52 GMT -5
CB... is it necessary to 'ground' one's self like working with a computer before changing an LED light bulb? I know those little zaps we get in the wintertime when the air is very dry, although not usually harmful to us, are low current but very high in voltage.
Another question: I know the input to a household LED bulb is ~120v.a.c. but is that changed to a low voltage d.c. when applied to the actual LED?
Having been a photographer for the past 59 years, I still prefer the good old tungsten bulbs with a continuous spectrum that is very controllable by filters and voltage. And the little zaps don't affect them at all. I know they're more expensive to operate, and have a heat disadvantage, but they're predictable and controllable, which a photographer needs. Today's CFLs and LEDs rarely have predictable color temperatures and they're usually quite different from one another which drives a camera (and a photographer) crazy.
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Post by Clipper on Jan 23, 2015 10:25:34 GMT -5
Our new travel trailer has LED's instead of the 12 volt automotive bulbs that the older units had. We are not happy with the overly bright and glaring quality of the light, and instead of paying a couple of bucks for a package of replacement bulbs, the lights in the trailer are $45 for a replacement according to the Camping World catalogue. Ridiculous is the first word that comes to mind. Travel trailer lights ARE converted from 120AC to 12v DC when a trailer is plugged into an RV park power supply. I am going to replace one of the units, that glares down on us in the living area with one of the old style that takes a filament automotive bulb. The LEDs are fine in the kitchen area or bathroom where you want a brighter light to shave or whatever, but offensive to the eyes in a living area where one wants to relax.
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Post by clarencebunsen on Jan 23, 2015 12:53:22 GMT -5
LEDs require a fairly low dc voltage to switch on, about 3 volts if I remember correctly. The circuitry in the base is what is needed to convert the 110 v ac to what the diodes need. Other differences between that & a filament: an LED is a point source, the filament is an extended source; a LED normally produces light in a very narrow bandwidth, a heated filament produces a broad spectrum (from infrared to near us) and the shape of the frequency distribution varies according to filament temperature.
I'm pretty sure what I killed with my static discharge was the dc supply circuit. When I think about it, that's not an unexpected problem but I didn't anticipate it. I don't think I will ground myself in order to switch that lamp, I'll use a different bulb type instead.
On going development challenges I see with LEDs. In order to achieve "natural" light it is necessary to blend diodes with different emission spectrums into the single "grains" you see in the bulbs. This continues to change seemingly every month. The bulbs are marketed with a color "temperature" which gives an approximation of the temperature a a tungsten filament with a similar spectrum. Some approximations are better than others.
Phillips has a line of bulbs called "Hue" which are advertised as producing a wide variety of colors from a single bulb. Supposedly you can do things like program a sequence for your bedroom lights to go through color changes like a natural dawn. I would love to play with something like that but when I looked it was something like $200 for a starter kit.
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Post by Clipper on Jan 23, 2015 16:10:59 GMT -5
Just to be clear Clarence, are you saying that the conversion from 110AC to 12DC happens at the base of the bulb and that changing my travel trailer fixture back to the old style would require rewiring to route the power to that particular fixture through the converter or inverter or whatever they call that stepdown apparatus?
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Post by clarencebunsen on Jan 23, 2015 17:14:32 GMT -5
I'm not sure. The bulbs sold for household use do the change from 110AC to 12DC in the base of the bulb. The only trailer I ever did anything with the electrical was the popup we had back in the 80s & 90s. That trailer was wired with 12V and used automotive bulbs in the fixtures. There was an inverter for plugging into campground power and a regular storage battery for off grid use. That was long before LED lighting. A voltmeter or the manual should tell you what you have at the fixtures.
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Post by Clipper on Jan 23, 2015 19:42:54 GMT -5
I will have to check the manual or call the dealer. I have the trailer safely wrapped in it's fitted RV Cover cocoon for the winter. It takes over an hour to put it on. There are zippered panels so that one can access the doors or compartments, but I am not going to disturb it until spring has sprung. Oops. I guess it will have to be a call to the dealer. I just remembered that the manuals are in a brief case in a compartment inside the trailer under the queen bed, haha.
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Post by clarencebunsen on Jan 23, 2015 19:53:12 GMT -5
You could probably find the manual on line but let the dealer chase the info.
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Post by Ralph on Jan 24, 2015 2:56:10 GMT -5
The birds hate the CFL bulbs so when I had to put a new bulb in my Macaws room I went with an LED. It was nice and bright in the overhead fixture and lasted less than a month. It winked out while I was home so I went to unscrew it and was quite surprised to find the base (which IS where the 110VAC becomes DC) was really pretty damn hot, easily as hot as a regular 100 watt bulb.  Needless to say I wasn't to thrilled with losing one that soon, nor with the heat it was throwing off either. I would up going back to a standard GE Reveal bulb as they seem to like that the best.  |
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Post by clarencebunsen on Jan 24, 2015 6:31:35 GMT -5
The total heat that LEDs put out is a little less than equivalent CFLs (perhaps 5 watts vs 6) but it is more concentrated. That's why many of the first designs had those honking big heat fins. Are the Reveal bulbs still being manufactured? I haven't paid much attention to bulbs which were designed for specialty uses: some for heat (incubators), some for particular spectral properties (birds, grow lights, aquariums, photography). I would imagine that as light bulb manufacture shifts to large factories in China, specialty bulbs will become harder to find and more expensive.
I think I have 3 aquariums in storage. One daughter had fish; one son had a lizard and the other a snake. It seems like I was always hunting for the right bulb.
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Post by corner on Jan 24, 2015 8:27:07 GMT -5
this summer I started using fire flies in a jar but they only seem to last 2 weeks apparently the life span of the little buggers however very good for the environment
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Post by clarencebunsen on Jan 24, 2015 10:43:52 GMT -5
this summer I started using fire flies in a jar but they only seem to last 2 weeks apparently the life span of the little buggers however very good for the environment Great idea! Now if we could only get them to eat kitchen scraps & produce lawn fertilizer. |
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Post by kit on Jan 24, 2015 10:59:10 GMT -5
Guys... you have to feed the fireflies or they'll soon become lawn fertilizer.
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