Excitation of electrostatic field is made up of static charge electric field. The static charge is called the source charge, referred to as the source charge. Electrostatic field electric field lines start at a positive charge or at infinity, ending at infinity or negative. Electrostatic field of electric field direction and source line charge has a close relationship. Source on the spot when the charge to the positive charge, electric field lines into the divergence of the electric field; when the source for the negative charges on the spot, the electric field lines of the electric field into convergence. Mobile field force charge characteristics of work has nothing to do with the path. Potential difference are used to describe properties of the electric field, or equipotential surface vividly illustrate the distribution of electric field potential.