where V Hall is the Hall voltage, I channel is the channel current, e is the elementary charge and h is the Planck constant. The divisor ν can take on either integer (ν = 1, 2, 3,...) or fractional (ν = ⁠ 1 / 3 ⁠, ⁠ 2 / 5 ⁠, ⁠ 3 / 7 ⁠, ⁠ 2 / 3 ⁠, ⁠ 3 / 5 ⁠, ⁠ 1 / 5 ⁠, ⁠ 2 / 9 ⁠, ⁠ 3 / 13 ⁠, ⁠ 5 / 2 ⁠, ⁠ 12 / 5 ⁠,...) values. Here, ν is roughly but not exactly equal to the filling factor of Landau levels. The quantum Hall effect is referred to as the integer or fractional quantum Hall effect depending on whether ν is an integer or fraction, respectively.