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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