From: ehsjr@verizon.net   
      
   On 8/23/2022 10:24 PM, bob prohaska wrote:   
   > Does anybody have a weblink for the temperature coefficient   
   > of voltage for commercial (Energizer) size 357 silver oxide-zinc   
   > button cells? Nominal is 1.55 volts, but knowing the temp effect   
   > is (maybe) important if I'm stacking up nine or ten of them.   
   >   
   > I'd like to check a trio of inexpensive Radio Shack DVMs for use   
   > in charging relatively-expensive lithium iron phosphate batteries.   
   > On the same battery the three meters report 14.41, 14.51 and 14.58   
   > volts, so they certainly disgree among themselves. I suspect but   
   > can't yet prove that the middle one is about 2% higher than actual.   
   >   
   > Yes, I probably should buy a good DVM, but the Radio Shack units   
   > are on-hand and except for charging batteries absolute accuracy   
   > isn't usually of much importance.   
   >   
   > Ten millivolts is plenty good for present purposes. If there's a   
   > better/cheaper improvised reference in this range please post!   
   > CR2032 cells are readily available, but voltage details are scarce.   
   >   
   > Thanks for reading,   
   >   
   > bob prohaska   
   >   
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   You want a precision that is doomed by the technique you   
   intend to use - stacking cells.  Instead, build a voltage   
   reference using a single IC:  ADR01 available from Digikey   
   https://www.digikey.com/en/products/detail/analog-devices-inc/AD   
   01AUJZ-REEL7/996117   
   It provides 10V output at +/- point one percent  (.1%)   
      
   Calibrate your meters to that.   
      
   Ed   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)