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
|