The diffusion equation is solved for transistors for (a) linear flow of minority carriers and (b) non‐uniform flow of minority carriers due to a metal contact applied to the base region. The current transport ratio &bgr; is calculated for both of these cases as a function of frequency.Frequency response characteristics of a transistor, as predicted by the one‐dimensional diffusion equation, give excellent results for junction transistors having base length‐to‐base width ratios greater than ten and having negligible surface recombination rates. For transistors where these conditions are not applicable, the two‐dimensional diffusion equation must be used in the calculation of &bgr;.