Electronic devices exhibiting bistability in the current‐voltage characteristics are considered from a unified viewpoint. We obtain simple relations for the stability of the different branches in the current‐voltage characteristics. Criteria for oscillatory instabilities are discussed, and special conclusions for elements with S‐ or Z‐shaped characteristics are drawn. The stabilization of the middle branch of the double‐barrier resonant‐tunneling diode in a circuit with effectively negative capacitance and negative resistance is derived in a simple way. ©1995 American Institute of Physics.