Mercury battery replacement circuit

[erker@xxxxxxxxxxxxxx (Greg Erker)]

Saw this on rec.photo.35mm.

I made my own adapter to use silver oxide batteries.  Here's how:

1.  Go to Radio Shack and buy a two sided copper clad circuit board
blank. These are used to etch PCBs.  Also buy a package of ten
germanium diodes (you only need one, but RS only sells them by 10).

2. Cut a somewhat circular piece of the circuit board with a jeweler's
saw or a pair of nippers.  It should be a little smaller than the
diameter of the battery so it will lay flat in the battery
compartment.  Cut one side of the circle flat to make room for the
diode, which you are going to solder to the board.

3. Solder the leads of the diode to opposite sides of the little piece
of copper board.  You now have an adapter which will drop the voltage
about .2 volts.

4.  Use silver oxide batteries, not alkaline.  I used a shim cut from
a piece of plastic tubing to get them to fit better.  If your camera
has a side contact like my Nikon F, you will need to make a metal shim
from a piece of wire.  I used some Sterling silver bezel wire for
jewelry making.

5. Insert the adapter into the battery compartment, then lay the
shimmed batteries over it.  If it doesn't work, try reversing the
adapter.  It will only conduct current one way (that is the function
of a diode, the voltage drop is incidental.)

I use these homemade adapters in a Nikon F and a Luna Pro, which both
take 2 batteries and they work fine.  I have not tried them in a
single battery application.

Bill Potter

---end---

Greg