Theoretical models for analyzing proto-transistor charge - storage operation

The purpose of this paper is to present and compare three distinct phototransistor models deemed suitable for analyzing the behavior of this device in the charge-storage mode of operation. The models are derived from a common basis by utilizing a set of relationships proposed by Giacoletto for describing large-signal behavior of a bipolar transistor, modified to account for photogenerated carriers. The resulting models, of varying degrees of complexity, are all mathematically tractable.