Multifuse devices act as circuit protection components by limiting dangerous current surges, such as short circuits, in electrical equipment. They provide protection as they react to an over-current event by changing from a very low resistive state to a very high resistive state. This is known as the positive temperature coefficient effect or PTC effect. What makes these devices special, is that once the over-current surge has passed, the Multifuse device will reset to its low resistive state again and allow the equipment to resume operation. Therefore, they are known as resettable fuses.