Some posible problems:
what type of device did you used ?
current?
current density of electrodes?
refference electrode position?
use EEG or TENS electrodes is bad idea they have wrong current density and resistence and dnagerous electrochemial products
use saline soaked electrodes of right current density
http://brmlab.cz/project/brain_hacking/tdcs http://www.longecity.org/forum/topic/50076-tdcs-thread/page__st__30__gopid__503859#entry503859
Fast track to pure focus
The journalist goes from
to
That hasn't stopped a vibrant community of DIY tDCS enthusiasts from springing up. Their online forums are full of accounts of their home-made experiments, including hair-curling descriptions of blunders that, in one case, left someone temporarily blind.