The physics
The electric field E at a point is the force on each coulomb there. A small + test charge feels it.
E = kq / r² (k = 9 × 10⁹ N m²/C²)
E points away from a + charge and toward a − charge. Fields from many charges add as arrows.
A dipole is +q and −q, a small gap d apart. Its moment p = qd points from − to +.
axis: E = 2kp / r³ equator: E = kp / r³ V = kp cos θ / r²
On the axis, E points along p. On the equator, E points against p and V = 0.