关于电子学，见触发器或复振器。

处于双稳的系统有两个平衡状态。在物理学中，对于全体粒子，双稳态源自于它的自由能有三个临界点。其中两个为最小值而最后一个为最大值。通过数学论证，最大值一定处于两个最小值之间。默认情况下，系统的态将处于最小值态两者之一，因为这样对应于系统的最低能量。最大值可以被看作壁垒。

最低自由能态之间的跃迁，需要某些形式的激发能来穿透壁垒（对照化学里的激发能和Arrhenius方程）。当穿越壁垒之后，系统将再一次静止到下一个最低能态。需要的时间称作弛豫时间（哪一个态将成为新态可能会有不确定性，但是通常情况下是被很好地定义了的）。

In a dynamical system, bistability means the system has two stable equilibrium states. Something that is bistable can be resting in either of two states. These rest states need not be symmetric with respect to stored energy. In terms of potential energy, a bistable system has two local minima of potential energy separated by a peak (local maximum). An example of a mechanical device which is bistable is a light switch. The switch lever is designed to rest in the "on" or "off" position, but not between the two.