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Old 13th Sep 2017, 11:50 pm   #21
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Join Date: Oct 2016
Location: Maroochydore, Queensland, Australia.
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Default Re: Measuring half wave voltages on Valve Testers.

Originally Posted by ms660 View Post
My old Hikock based I-177b valve tester used full wave rectification for the HT and full wave rectification for the grid bias supply, the HT via a mercury vapour rectifier to keep the supply impedance low to the DUT
The genius of Hikock's patented system was the fact that all of the voltages in the one unit were derived from the one mains transformer and the unit could be calibrated perfectly accurately with just setting the meter circuit calibration, it does not require a reference transconductance device. I wrote a detailed article on this and why this is so and the Hikock's basic circuit including remarks about the anode and grid voltage waveforms under different bias settings, which may be of some interest to the OP:
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Old 14th Sep 2017, 12:48 pm   #22
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Default Re: Measuring half wave voltages on Valve Testers.

Am I seeing a mistake in this from the WD technical manual TM 11-2627 ?

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Old 14th Sep 2017, 1:43 pm   #23
David Simpson
Join Date: Mar 2008
Location: Aberdeen, UK.
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Default Re: Measuring half wave voltages on Valve Testers.

Many thanks Argus25 for the great Hickok article. A "must read" for all valve testing enthusiasts.
Lawrence and Bill, how far apart are you from each other down there in the remote SE of England ? Or perhaps there are other valve testing enthusiasts nearby ? A "one to one" with Bill to examine his valve testing issues might be a great help. There is nothing to beat a cuppa, scone & chinwag amongst fellow Forum guys in remote corners of the UK. I can vouch for that.

Regards, David
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