Balls labeled "1" and "3" are in two stable positions
In a dynamic system , bistability means that the system has two equilibrium states. A bistable object can rest in either of these two states. These rest states do not have to be symmetrical with respect to the stored energy. In terms of potential energy , a bistable system has two local minimums of potential energy, which are separated by a peak (local maximum). An example of a mechanical device that is bistable is a light switch . This switch is designed to remain in the On or Off state, but not between them.