[Amps] Holding a vacuum

[Gerald Williamson via Amps]

Hi Karin. the direct answer is the tube will withstand application of the  
rated hv with only a few microamperes of leakage current showing.
 
The non-destructive test method is use of a high voltage breakdown tester.  
They have the means to vary the applied voltage with a current limiting  
resistance to prevent a damaging flash over.
 
The test is done with the tube cold and out of the equipment. A good tube  
will withstand rated voltage and a gassy tube will show leakage current with 
 less than 1500v typically. Withstanding rated voltage would be about 2X 
the  expected operating voltage or more.
 
If you decide to just go for broke and apply the full plate voltage you  
shouldn't be surprised if there is a big KAPOW event resulting in damaged  
components in the amplifier and/or power supply.
 
73,
Gerald K5GW
 
 
 
 
 
 
 
In a message dated 12/1/2014 9:03:08 A.M. Pacific Standard Time,  
karinann at tampabay.rr.com writes:

What  metric does one use to determine if a given tube holds a vacuum or  
not?




Cheers,

Karin    K3UU

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