Just picked a really excellent new “toy”, a key-chain flashlight using no batteries and a small industrial sapphire. Makes quite a bit of bright, deep blue light, almost like a blacklight.
Can such a thing be made with an industrial ruby, getting a red light ? BTW, what “starts” up the crystals’s oscillation ? [i.e. how does it work ?]
Whatever the source, there has to be energy being input from somewhere, or you wouldn’t get light out.
No battery?
Are you standing close to an occillating magnetic field?
Did they embed radiactive material so that it’s decay excites the material into luminescence. Reguardless both of the above wouldn’t allow the light to be shut off.
Will the light function if it’s cold? A dielectric element could be used to power an oscillation, if the light only functions when not cold.
The makers have perfected Tesla’s power transmission through air, and the device draws it’s energy from a device they have at their headquarters.
Judging by the thread topic, I’d guess it’s Piezo-electric, wouldn’t you? 
Certain crystaline structures produce electricity when subjected to pressure. Piezo-electricity is what provides the spark for electric lighters and when you chew wintergreen Lifesavers in the dark.
I’m curious, does the light gradually dim if you don’t ‘activate’ it from time to time? Is there an on/off switch, or more of a ‘trigger’ like an electric lighter?
Stephen
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Sorry, didn’t mention it… there’s a switch, of course (it’s a flashlight), when depressed, bright light, when released, no gradual dimming that I can perceive (doesn’t mean it ain’t there…). I s’pose the switch triggers a coil/spring/somesuch to vibrate the lil’ crystal… but is it restricted to short-end of visible light spectrum ?
Piezo crystals only work with a short, sharp, smack like those used in cig lighters and barbeque propane lighters. I’d bet if you opened the thing up there’s a battery inside.
That’s what I was thinking Doc. The only ones I come in contact with normally is the ignitor on the BBQ grill. The trigger mechanism whacks the hell out of the crystal and about 1000 volts are generated, judging by the 1/2" spark.
I suppose you could charge a capacitor, then bleed it off slowly thru the lamp, but there would be a decay soon as the capacitor discharged. And it would seem like it would take a rather large capacitor to power any lamp for a reasonable length of time.
One of the reps for a crystal company where I was formerly employed attempted to get us to market a flashlight powered only by piezoelectricity. To operate the thing, it was necessary to continually squeeze the trigger mechanism in and out–similar to squeezing a tennis ball for the exercise. IIRC, squeezing the trigger wound up a spring, which then relaxed. On both tension and relaxation, the spring caused a cam mechanism to operate. The cam smacked the crystal, electricity was generated and the flashlight bulb illuminated. We chose not to market the thing and all of this took place some twenty years ago so the finer details are gone. If the device under discussion has only a on-off switch, I fail to see how the lighting mechanism can be soley dependent on the piezoelectric effect.
Crystalguy
A piezo crystal has a “recovery time” before you can fire it again. They used to use them in tractor ignition systems (still might) but not in cars because of the higher RPM of a car engine. We used to use some pretty big ones in the lamp resarch lab and they’d hold a charge for months like a capacitor. One of the standard “lab humor” tricks was to charge one up and leave it on the newbie’s bench and watch him get shocked when he picked it up. hee hee
“Hope is not a method”
Well, if you mean these:
http://www.knives-express.com/build/Flashlights/ASP_Sapphire_Lights/index.html
I’d have to say that they are not piezoelectric, mostly because they guarantee the battery for life. They do look like cool toys, though. Probably hell on your night vision.
More on the sapphire ASP lights based on some web-browsing.
Ummm, as usual for me I read the dictionary first:
pi•e•zo•elec•tric \pe-‘a-(’)zo-e-"lek-trik, pe-‘at-(’)so-\ adjective [ISV] (1883)
: of, relating to, marked by, or functioning by means of piezoelectricity
pi•e•zo•elec•tric•i•ty -'lek-"tri-s(e-)te\ noun [ISV] (1883)
: electricity or electric polarity due to pressure esp. in a crystalline substance (as quartz)
©1996 Zane Publishing, Inc. and Merriam-Webster, Incorporated. All rights reserved.
1883??? Wow, old!
Handy—piezoelectricity (but not by that name) was proposed as a theory sometime prior to 1880. No one is completely sure who first mentioned it. But the Curie brothers conducted experiments using slices of different crystals. Some primitive electrodes (tin foil) were placed on the slices and weights were placed on the electrodes. A deflection of the needle of an “electrometer” proved that the phenomena did exist. Their paper proving the theory was read before the “societe mineralogiqe de France” in April 1880. It was only after the paper was read that the name “piezoelectricity” was proposed and adopted. Producing electricity by mechanically straining the crystals lattice structure is called the “direct piezoelectric effect.” Sometime after the Curies read their paper, a person named Lippmann postulated that the reverse of the “direct piezoelectric effect” existed. The Curie brothers conducted further experiments and proved that this was true. In other words, straining the crystals lattice structure by the application of an electric field was found to be practical. And, and this is important, it was found that if the electric field was made to alternate, so did the strain, changing signs with the alternating current. The straining of the lattice structure by the imposition of an electric field is known as the “obverse piezoelectric effect.” Of the thirty-two classes of crystal, twenty-one are piezoelectric. Quartz, for a plethora of reasons is the material of choice for crystal units used in the field of frequency control. Take a look at my website if you have time. http://www.crystalguy.tripod.com
Piezoelectricity is a remarkable phenomenom that is little studied and seldom taught. In fact, the basic text book has been out of print since sometime in the forties, I believe.
Crystalguy
Doctordec, I forgot to say that some sort of recovery time may be a requirement for some types of piezoelectric crystal, particularly the ones used to emit a spark–those devices are usually made from a piezoelectric ceramic, I believe. Quartz crystals, as used in the field of frequency control, will operate nonstop for as long as their parent device is operating. These devices are utterly fascinating.
Crystalguy