  We study the effect of electric charge in compact stars assuming that the
charge distribution is proportional to the mass density. The pressure and the
density of the matter inside the stars are large, and the gravitational field
is intense. This indicates that electric charge and a strong electric field can
also be present. The relativistic hydrostatic equilibrium equation, i.e., the
Tolman-Oppenheimer-Volkoff equation, is modified in order to include electric
charge. We perform a detailed numerical study of the effect of electric charge
using a polytropic equation of state. We conclude that in order to see any
appreciable effect on the phenomenology of the compact stars, the electric
fields have to be huge (~ 10^{21} V/m), which implies that the total charge is
Q ~ 10^{20} Coulomb. From the local effect of the forces experienced on a
single charged particle, it is expected that each individual charged particle
is quickly ejected from the star. This in turn produces a huge force imbalance,
and the gravitational force overwhelms the repulsive Coulomb and fluid pressure
forces. The star can then collapse to form a charged black hole before all the
charge leaves the system.
