Re: What is a Solid State Emmiter?

Bill wrote:
jim beam wrote:
Bill wrote:
jim beam wrote:
Bill wrote:
And here is a white at 3.5 volts.
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=183231


There is also a link to a PDF file to show the wavelengths and chemistry. This manufacturer, whom I have never heard of before, does not use a simple LED to energize a flourescent to get white, as some have suggested, but puts out a spectrum that is heavy on the blue end.

I could post more from Jameco, Mouser, Allied, etc....., until people got sick of the subject.

Bill Baka


but that's the point! the larger the band gap, the larger the voltage required! you change chemistry to change the band gap and voltage varies accordingly!

I know that, but part of my point was that the number of chemistries is growing as people search for real 'white' light, and not the blueish tint that was shown in the pdf I pointed to, or a super efficient and bright chemistry that will surpass all previous attempts. All of the traffic lights in my somewhat backwater town have gone to single wavelength red, yellow, green that can be seen even in bright sunlight.
I have only seen one light with one burned out LED in the green and they don't see fit to replace it since it has been like that for over 2 years.
Mainstream LEDs emit in one very tight wavelength, kind of the light version of a radio crystal.
Even I don't want to try to calculate the band gaps that are used all over the map, like the Jameco part I referred to. That one tries to be white and the spectrum is not a spike at one wavelength but a wide blue tapering off on the red end of things. I had to download Chinese fonts for my Acrobat just to see the whole data ***, and I only want to spend so much 'unpaid' time on research.
Pay me and I will make a spread*** of every LED ever made and the band gaps of all the possible materials.

so what? doesn't mean a thing if you don't understand what you're looking at!

I found out long ago that you can't learn everything and anyone who claims to is either an idiot or lier.

ok...

I'm an E.E. who just uses the parts so I don't need to know all the band gaps.

so how do you design if you don't know theory?


I do get paid for designing circuits that use these parts

ok...

and I am very money motivated.

that's logically irrelevant!




There are probably only a handful of people who care what makes the light as long as it works.
I'm one since I have a Cat-Eye 5 LED setup with through hole white LEDs and I might want to upgrade it if I can find some better white LEDs.
I was also thinking of building a miniature boost/buck universal converter to drive the LEDs at whatever brightness I wanted to dial in with an old fashioned pot. 3.3 volts on the LEDs, 4.8 volts from my NiMH batteries, and 6 volts from Alkalines. I wouldn't mind sucking the Alkalines for their last gasp, but the NiMH rechargeables might not like that very much.

irrelevant.

Only if you want to buy new rechargeables every week. Kind of defeats the purpose. I haven't seen any bicycle headlights that claimed to have an active circuit for maximizing either battery life or brightness or even just a level adjust other than a high/low resistor switch.

it's irrelevant to led/incandescence differentiation!




OK, enough electronic stuff.

please bill, please.


How about enough physics stuff from you then?

then stop bullshitting then! then.
.

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