[Amps] Glass envelope

[Ian White GM3SEK]

GGLL wrote:
>k7fm escribió:
>> "Sorry if this is a silly question, but, which is the criteria for sizing
>> (mainly its diameter) glass tubes envelope?. One can see a glass
>> envelope in
>> an 813 tube relatively near the plate electrode, but for 3-500z or RS-1019
>> tubes, those are fat indeed. TIA"
>>
>> I am speculating, but - tubes that run red or white have more spacing
>> between the plates and the glass.  304TL, 75T and 3-500Z tubes run at a
>> higher temperature and the plates need to be further away from the glass.
>>
>> Now, the next question is - if a one vacuum tube has more volume inside
>> than another, does it have more or less vacuum?
>
>Does it still has nothing?. So it must be equal regardless inside 
>volume.
>

Nothing?

Tubes are typically pumped down to about 1E-8mmHg, which means that the 
"vacuum" space of an amateur-sized transmitting tube will contain well 
over a million free gas molecules.


-- 
73 from Ian GM3SEK         'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek