 In the NPN transistor in what is called active mode, the base–emitter voltage formula_10 and collector–base voltage formula_13 are positive, forward biasing the emitter–base junction and reverse-biasing the collector–base junction.In the active mode of operation, electrons are injected from the forward biased n-type emitter region into the p-type base where they diffuse as minority carriers to the reverse-biased n-type collector and are swept away by the electric field in the reverse-biased collector–base junction.For a figure describing forward and reverse bias, see semiconductor diodes.