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The Never-Ending Light Bulb

The headline might be a slight exaggeration. But only slight:

Ceravision has just announced that they have developed a lightbulb that is 50% efficient (more than twice the efficiency of CFLs) and will last...um...forever?

No, that can't be right, but a very very long time anyhow. They say they expect their new lamp to outlast whatever device they put it in, so apparently your lamp will break before the bulb does.

So can the never-ending lamp be far behind? So how, exactly, does this thing work?

The device doesn't use any fascinating new technology, which is really good news as it can be built from parts already in mass production. It's a new sort of metal halide lamp (a tube of gas inside a lump of a metal oxide.) When the lamp is put in the presence of a microwave emitter (just like the one in your kitchen, but much smaller) a concentrated electric field forms in the tube of gas which promptly turns into plasma. More than 50% of the energy is emitted as light, which is 2x more than ordinary metal halide lamps, and four times more than ordinary fluorescents.




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Since people with pacemakers are supposed to stay away from microwaves, what would be the affect of this lightbulb on them? What kind of cost are we talking about here for this lightbulb?

Uh, I think you got your numbers wrong.

Halide lamps are not 2X as efficient as CFLs.

Second - Tesla did this over 100 years ago (with higher voltage and lower frequency - no filament required).

Third - Is pumping your house full of microwaves a good idea? How will you shield it?

Fourth - do you really think the microwave generator will have a million hour MTBF? Or better yet to keep returns and customer complaints low a 10 million hour MTBF? The bulb might last that long. How about the rest of the eqpt?

How many units did they test to arrive at their "forever" number?

The "pacemaker" and microwave oven was nonsense when it came out and still is now. Most up to date businesses have taken the bogus signs down.

And it wont "pump" your house full of microwaves or run out the door in a stream...after all, when you have an open outlet, little electrons dont pile up on the floor.

The mw generator is enclosed as are the mw in your oven. They are trapped inside the little screen with holes in it so you can look inside. As long as the holes are smaller than the wavelength they can not get out...


1. Well, they're not my numbers; I'm just quoting them. However, I think it's generally agreed that Halide lamps are more efficient than fluorescents.

Fluorescents will run anywhere from 50 lumens per watt up to about 95 at the extreme high end. CFLs usually run about 60. Halide lamps get you anywhere from 65-115. So at the top of the range, halides are close to being twice as efficient as CFLs, but the numbers are going to vary.

2. Hmmm... if Tesla did it, I guess that proves it's not a good idea. Or that it is. No, wait. Well, I'm sure there's some relevance to the fact that he did it. Or possibly not.

3. I don't know the answer to the microwave question, but I now have a pretty good idea (thanks to both you and Dick) what spin the conventional light bulb manufacturers will put on this thing should it go into widespread production and distribution.

4. Let me help you out, here. The correct wise-guy question to ask in this context is not how many they tested to prove that the bulbs last forever, but rather how they could prove even one lasts forever. Did they use a time machine, jump out to the end of time, and observe the bulb still there?

Not to show off or anything, but I bet I was asking pain-in-the-ass wise-guy questions long before you were born!

Ohhkaaay, Phil beat me to the punch.....

I was going to say to M. Simon:

1) Fluorescent lights (per my copy of an electrical engineer's handbook, published in 1957) were about 16% efficient, so 25% efficiency in this modern day of 2007 is not unreasonable, which in turn makes these metal-halide lamps (at 50% efficiency) twice as efficient as fluorescents.

2) You can do something similar to Tesla's trick today. Go find an amateur radio operator who has a VHF/UHF transmitter of modest power (100 watts or so) feeding a Yagi antenna (think "rooftop TV antenna"). Put a 40-watt fluorescent tube a few feet from the "business end" of the Yagi and ask the operator to key the transmitter. The effect is pretty neat, especially at night with the operator transmitting a Morse code signal. BLINK-BLINK-BLIIIINK-BLINK....

3) Uh, your microwave oven doesn't spew microwaves all over your house, does it? Then why should this light, especially when it's much less powerful than the 1500-watt monster in the oven?

4) MTBF times can be hard to judge, but seriously-- how many customers will be back, claiming that the light didn't meet a million-hour MTBF specification? In the year 2130 or so? Not very many, dude, even if Phil is right about lengthening lifespans.

Yeah, I'm a cranky SOB sometimes. :)

"Is pumping your house full of microwaves a good idea?"

Do you have a cordless phone, a Bluetooth headset or WiFi? Then you're already pumping your house full of the exact same 12.5cm waves a microwave oven uses.

For relative efficiencies of various light sources, there are tables at any of the marijuana-growing forums (I don't have any links - honest). The consensus is that flourescents draw conspicuously more electricity than halide lights and are to be avoided for all but the smallest of setups.

I stand corrected on the metal halide bulbs. I was confusing them with halogen.

Faboz et. al.,

I'm not worried about milliwatts. And yes screens are nice for keeping Micro Waves in or out. However, they represent an efficiency loss for emitted light.

You don't really need microwaves to get a discharge. A few hundred KHz will do. Easier to shield too!

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