Analytical model of collector current density and base transit time

Based on an iteration method with initial low injected minority carrier profiles, analytical expressions of collector current density and base transit time are presented. Comparing the analytical results with the numeric, the following conclusion is obtained: under the condition of injected emitter-base junction voltage V/sub BE//spl les/1.0 V, the analytical expressions of the collector current density and the base transit time with three time iteration processions are valid.