To all  (especially new members)
You can make a Controlled Current Generator with and Wall  DC power supply
using
a Current Regulating Central Diode they come in various currents 610-1N5297
from Mouser Electronics is for 1 Mill amp
You put this in line with power supply with a volt meter you can measure
voltage (higher as Silver is further apart and lower as you move silver
closer together). It adjust voltage to matain  mill amp rating.
 
  Bob