A study of two-terminal current-controlled negative resistance devices with the aid of an analogue

Some fundamental aspects of current- and voltage-controlled negative resistance devices are considered, in particular the relation of the physical mechanism involved to the equivalent circuit. Further, a unified stability criterion is presented which is applicable to both types of device. A versatile analogue of a current-controlled device is described which is compatible with a voltage-controlled analogue previously described. The high-frequency properties of this analogue are examined both experimentally and theoretically to determine the variation of the equivalent circuit parameters with frequency. With the aid of the analogue two circuit configurations are examined: a bistable trigger circuit, and a four-stable-state circuit obtained by the addition of a voltage-controlled analogue. It is believed that the techniques described enable circuits to be investigated at relatively low speeds, thus facilitating the optimization and understanding of a given configuration.