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[AMPS] Anode current vs cathode current...

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Subject: [AMPS] Anode current vs cathode current...
From: G3SEK@ifwtech.demon.co.uk (Ian White, G3SEK)
Date: Tue, 3 Mar 1998 17:13:02 +0000
Skip wrote:
>>I'm just trying to understand if there is an specific advantage/reason
>>for the mention of  anode vs cathode.

Rich replied:
>By measuring anode[plate] current, one can see if the tube is being 
>driven to the max rating.  There is no max. cathode current rating to 
>compare with, although there probably should be, Skip.  

What Rich says is correct (the whole posting) but I wonder if that's
what Skip really meant to ask.

There's a possible misconception that if you measure current in the B-
minus rail, down close to the cathode, you must be measuring cathode
current. That's not true (unless it's a very unusual metering circuit)
because the return current flowing back into the B-minus rail is
precisely equal to the current flowing out of the B+ rail and into the
anode. In other words, you really and truly are measuring anode current.

73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.demon.co.uk/g3sek

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