Point charge Q at distance r: V = $\frac{kQ}{r}$. Uniformly charged ring (Q, radius R) on axis at distance x: V = $\frac{kQ}{sqrt}$($x^2$ + $R^2$). Uniformly charged sphere outside (r >= R): V = $\frac{kQ}{r}$ (point charge behavior). Inside solid sphere (r < R): V = kQ$\frac{3R^2 - r^2}{(2R^3)}$ — note V is maximum at center: $V_{center}$ = 3$\frac{kQ}{2R}$ = \frac{3}{2}$$V_{surface}. Inside hollow sphere: V = $\frac{kQ}{R}$ (constant, equal to surface value). Electric dipole at far point (r, theta): V = kp*cos$\frac{theta}{r}$^2. Axial: V = $\frac{kp}{r}$^2. Equatorial: V = 0 (the equatorial plane is at zero potential for a dipole). Key insight: V decreases as 1/r for point charge but as 1/$r^2$ for dipole — dipole potential falls off faster.