I wrote
...
I believe the whole thing can be built in form and size of a electrical
tooth brush
...

I must correct myself: This current (at DC or LF anyway) is lethal if you
hold the device in your left hand unless the treatment is *very* short pulses.

Maybe make the unit so it front end is a metal plate with a one cm hole in
it, and in center the needle.  The plate is return for the current.

How are the units on the market made?
Are there safety requirements?
/Morgan
/  Morgan Olsson, MORGANS REGLERTEKNIK, SE-277 35 KIVIK, Sweden \
\  mrt@iname.com, ph: +46 (0)414 70741; fax +46 (0)414 70331    /