[time-nuts] LED Spectra mentioned in time-nuts Digest, Vol 66, Issue 164

Thomas A. Frank ka2cdk at cox.net
Sat Jan 30 16:06:16 UTC 2010

> I'm curious to know a little more about what was used to measure  
> the LED spectra.  Not familiar with a "diode spectrometer" and  
> Google is not being very helpful.  The last time I measured optical  
> spectra was a long long time ago using a PE UV/Visible  
> spectrophotometer in the early days of semiconductor manufacturing  
> - used it to measure dielectric thickness (on 1 inch and eventually  
> 2 inch wafers).  I'm interested in looking at the spectra of CF  
> lamps - something which may not be realistic since we retired folks  
> no longer have access to the fun (and expensive) lab equipment we  
> used in our pre-retirement days.

I too would like to know more about the tool used to create those plots.

What I use is a 'manual' direct vision spectrophotometer which I  
bought from Surplus Shed:


for $49 you can't really go wrong...however, when I have a bit of  
spare coin I plan on buying a better one:


You see, the $93 one actually has a scale in it, the cheap one does not!

They also sell much higher grade ones for $200-400 that do a good  
deal more (angle measurements etc).

But nothing that attaches to a computer for pretty plots.  So I'm  
intrigued as well.

Tom Frank, KA2CDK

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