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[OM] Accurate voltage convertor for OM1(n)

Subject: [OM] Accurate voltage convertor for OM1(n)
From: "Radovan Faltus" <faltus@xxxxxx>
Date: Fri, 24 Oct 2003 12:34:28 +0200
Hi all,
  There is one simple way how to convert 1,6 V 
voltage of silver-oxide cell to 1,35V which 
OM1 requires: to put serial Schotky diode
(they do this even in Olympus service center in Prague and it is
principle of the MR-9 adapter),
but it results in non-linear  error over all EV range(somewhere
less, somewhere more) as it's described in
Tim Huges report on Mark Dapoz's web. Let alone when your fresh battery has
1,82 V!!
  
  I think i've found better, accurate solution with low-voltage reference 
adjustable
"diode". It consists of one 3-pin reference part and 3 resistors.
  Disadvantage: necessary to place cirquit behind 
the main switch, means under the top plate.

Who is interested take a look here:
http://www.national.com/pf/LM/LMV431.html
- parts are available as samples for free ("I" - industrial types are better).

Download pdf datasheets, the schematic is Fig. 2, page 3.

My suggestion is: Rz = 270R, R1 = 20k, R2 = 240k.
Average consumption ...1 mA, so it will work 150 hours with
one SR44 (silver oxide).

Another similar part is LM385.

Radek 




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