here it is
hi,
there are two kind of charges, 1. the static( not running), running that is an current when charged particles are running under effect of some electric field. when charge is static it causese to form a electric field around it. by physics we know , under a field every point has a potential. when ever the permiablity of surrounding is not enough to keep this charge isolated from other things it causes a discharge through the surrounding called as electro ststic discharge.
abhishek