Modifying Camera to Accomodate Silver Oxide Batteries
by Jean Colin

Battery choice:

• Mercury battery was choosed by camera manufacturers because they have a very stable voltage, and this allow a very simple electrical circuit (a galvanometer). In adition, they had a high capacity
  
• Actually, the silver oxyde battery has the same voltage stability, but voltage is increased (1.55V instead of 1.35V)
  
• For recent camera design, electronics is so cheap that it is probably cheaper to enhance design to accommodate with voltage decrease of alkaline batteries than to include silver-oxyde batteries in the camera package.

How to modify

We need a galvanometer with one changed caracteristics, a sensibility decreased of 13%.

Below, you have two possibilities, and value calculated for a 10000 Ohm galvanometer.

Practically, calculated values are to be rounded to available resistors
1481 Ohm -> available 1,5 kOhm 5%
77500 Ohm -> available 75 kOhm 5%

1290 Ohm -> available 1,3 kOhm 5%
67500 Ohm -> available 68 kOhm 5%

If your galvanometer has a different resistance, you have to multiply thoses calculed values by the ratio betwenn your resistance and 10000 (my example).

10000 -> 1481;77500 1290;67500
22000 -> 3258;170000 2838;148500

Then you have to take the soldering iron...

The other problem is to have a mechanical adaptation of the battery chamber