Re: 7S14 - diode?

Chris van Lint

Thanks to Arthur and Ashton. From the answer it appears that the 1.35V does appear to be critical and the idea of using a Ge diode in series is an ellegant solution. Actually there are "Wein Cell" Zinc Air replacement cells with a terminal voltage of 1.35V around for use in cameras such as the SLR Pentax. The problem is that they are not available with solder tabs.


----- Original Message -----
From: Ashton Brown
To: Tekscopes
Sent: Saturday, May 19, 2007 8:32 PM
Subject: Re: [TekScopes] 7S14 - diode?

Nor do I recall the recent bat. ref. (It may well have been under a
useless successive title like, 'Thoughts on the Turbo Encabulator in

What I do recall is - successfully replacing a Hg-cell in a fine Pentax
SLR - with a ~1.5 cell of ~ size (Ag-Zinc or other.) Inserted a handy
Germanium diode in the body, where there was plenty of room == readings
well within cal (having applied precision 1.35 volts before, then
comparing post-op metering.)

While zeners could be tricky in camera use, where few-µamp drain is
preferred - one might work in your ap. as well as Ge trimming (?) since
power is free.

(I wish that Hg cells were still available.. maybe only with 'trade-in'?)
Then again -overall- I don't: we have proven that people will not
responsibly dispose of Anything. It's just too hard to think; takes time
away from shopping.


Chris van Lint wrote:
> One of the 1.35V bias batteries in my unit has failed. I searched the
> archives, because I remember there was some discussion on the replacement
> issue a few months ago. However I do not seem to be able to find a
> solution. I did send a message off line to one of the people who I thought
> was involved in the discussion without success. Does anybody on the list
> know whether a solution was found? Is the 1.35V critical, or could 2 x 1.5V
> alkaline cels be used.
> Chris

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