A Positive Temperature Coefficient or PTC Device is a resettable overcurrent circuit protection device. It is a series element, made of a conductive polymer that is placed in a circuit. Under normal conditions, the PTC Device has very little resistance and has little influence on the circuit. The PTC Device changes or trips from a low resistance state to a high resistance state in response to an overcurrent condition. In its tripped state, there is a sharp increase in the resistance of the PTC element and the current is reduced to a safe level. After the overcurrent state is removed, the device cools and returns or resets to its normal, low resistance state.

PTC Devices are offered in surface mount, radial leaded, battery strap (axial-leaded) and blade type versions. Telecom versions are offered in surface mount and radial leaded packages. Automotive versions are offered in surface mount, radial leaded and blade type configurations. A radial leaded Line Voltage Rated PTC Device is also offered.

Littelfuse offers the entire range of PTC Devices. The PTC Device is also called a Polyfuse®, a PPTC Device, a Polyswitch®, a Multifuse® or a PTC Resettable Fuse. Below is a sampling of the various configurations offered:

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Surface Mount PTC

Radial Leaded PTC

Battery Strap PTC

Telecom PTC

Automotive PTC

Line Voltage Rated