Criteria for stability in bistable electrical devices with S- or Z-shaped current voltage characteristic

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. (C) 1995 American Institute of Physics.