For an electrode with a 2 cm2 area in solution, the variable resistance in the circuit is adjusted to maintain an 80 µA current during deposition for a specified number of seconds.
Parts list from http://www.mouser.com
Battery Holder, Mouser 534-139
50 k-ohm 10 turn potentiometer, Mouser 594-53411-503
Banana Jacks, Mouser 530-108-0907-1
Aligator Clips, Mouser 548-30-BL
ON-OFF-ON through hole Toggle Switch, Mouser 633-M201303
This version incorporates and on/off switch.