Homebrew PCBs

Stefan Trethan wrote:

>On Fri, 6 May 2005 14:57:54 -0400, Roy J. Tellason  
><rtellason@...> wrote:
>
>  
>
>>>Light bulbs contain inert gas at atmospheric pressure.
>>>      
>>>
>>I was of the impression that it was at somewhat lower than atmospheric
>>pressure,  otherwise you wouldn't get that "pop" when they break.
>>
>>    
>>
>
>It is lower than athm., put a propane torch against it and the softening  
>glass will be pulled in.
>(yes i am aware that experiment could have resulted in shattering hot  
>shards and be beeing blind...)
>There's Argon in there.
>
>  
>
>>The other
>>reason it's that thick is because of lead in the glass to absorb  
>>x-rays,  at
>>least for color tubes,  which is what makes TV sets and monitors a bit
>>"hazmat" rather than just being able to put 'em in the trash.  Monochrome
>>monitors and old B&W tv sets don't have that issue.
>>    
>>
>
>
>Why is x-rays created, and why is it not beeing created in BW TVs?
>Always wondered..
>
>Hell this is getting OT.. maybe we should take it to E_101.
>
>ST
>
>  
>
B/W tv's used 15Kv or so accelerating voltage - created soft x-rays.  
Color sets needed more energetic electrons for the color phosphors, so 
used  ~23Kv, IIRC, and generated harder x-rays. The x-rays are only 
generated while the HV is on - they are not residual.  Any hazmat must 
be in the toxicity of the phosphors used to generate the colors.

Norm


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