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Old 19th Feb 2010, 11:32 pm   #173
swordholder
Rest in Peace
 
Join Date: Aug 2009
Location: East Preston, Sussex
Posts: 162
Default Re: The "Sussex" Homebrew Valve Tester.

JOHN
In answer to your questions
(a) The voltage stays pretty constant whether a valve is in or out of the tester.
(b) The Constant current supplied to the zener chain supplies a smooth supply to the anode and screen voltage switches, which in turn contol the gate of the mosfets. I havent measured ripple and noise, but valves tested and compared with a VCM163 indicate that all is OK
(c)The sine wave is applied to the grid through C7 and is adjusted by VR2

Hope this helps

Regards
Mike
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