An electric dipole consists of two equal and opposite charges q and –q separated by a (small) distance 2a. Its total charge is zero.
The potential due to the dipole is,
Taking r1 and r2 = r2+ a2 ± 2arcosθ
where p =2qa
(Positive sign for θ = 0, negative sign for θ = π.) The potential in the equatorial plane (θ = π/2) is zero.