Abstract: The error in the formula of the charge distribution linear density of a finite-length charged linear conductor in the literature is pointed out, and a variety of methods are used to prove that the charge distribution of the charged wire section is uniform. The equipotential line equation and electric field equation of the uniformly charged section are deduced, and it is proved that the charged section is the equipotential line, and the electric field line is perpendicular to the line section. It is proved that the electric potential outside the line segment satisfies the three-dimensional Laplace equation, so as to prove that the uniformly charged line segment is a conductor.

Key words: charged straight line, charge density, projection method, electric potential, dimensionless drawing