resettable

Resettable describes the ability of a device, system, or component to return to its original operating state after a fault, interruption, or intentional reset. In electronics, the term is commonly applied to protective devices and features that can recover without replacement.

A resettable fuse, also known as a polymeric positive temperature coefficient device or polyfuse, provides overcurrent protection. Under normal operation it has low resistance, but when excess current flows it heats up, increases resistance, and limits further current. After the fault is removed and the device cools, it returns to its low-resistance state and can be used again.

Resettable circuit breakers are protective devices that interrupt current when an overload occurs and can be reset after the fault is cleared. They may be thermal, magnetic-thermal, or electronic in design and can reset automatically or require manual intervention.

Beyond electrical protection, resettable can describe software constructs and user interface features that restore default settings or restart a process. In product design, labeling something as resettable signals that the function or protection can be restored to its initial state without needing replacement parts.

Compared with non-resettable counterparts, resettable devices can reduce maintenance costs and downtime, though they may have different response characteristics and fault current ratings. Standards organizations such as UL and IEC publish specifications for resettable components, including trip characteristics, current ratings, and environmental limits.