where "I"0 is the reverse saturation current. Where the two parameters that depend on the solar cell construction and to some degree upon the voltage itself are "m", the ideality factor, and "kT/q" the thermal voltage (about 0.026 V at room temperature). This relation is plotted in the figure using a fixed value "m" = 2. Under open-circuit conditions (that is, as "I" = 0), the open-circuit voltage is the voltage at which forward bias of the junction is enough that the forward current completely balances the photocurrent. Solving the above for the voltage V and designating it the open-circuit voltage of the "I–V" equation as: