Multivibrators are simple two-state devices commonly considered digital logic components, though their typical manners of use are largely analog in character. Monostable types, also called "one-shots", have one stable state; though application of a trigger signal can cause them to leave this state for a period of time usually determined by the value of a connected capacitor. These are useful for applications such as de-bouncing switch contacts. Astable types have no stable state, and transition between two states continuously at a frequency which again is usually determined by the value of a connected capacitor.