Common emitter breakdown

A theory of the current-voltage characteristics with grounded emitter and open base is developed in a first approximation form. The results show the typical negative resistance region characteristic of these
I-V
curves, and the theory indicates the important parameters which control this negative resistance. The containment of the emitter current with subsequent development of "hot spots" on the transistor becomes easily understood. Experimental evidence of the importance of localized breakdown spots in common emitter breakdown is presented.