Positive Thermal Coefficient devices(PTC),provide over-current protection for electrical and electronic devices. They function using conducting strips of metal imbedded inside polymers.
Under normal conditions, the devices resistance is near zero, but over-current conditions will heat the PTC and expand the polymer, increasing the impedance. When current returns to normal, the components cool down, returning to their original shape and very low levels of resistance.

Features:

I(hold): 0.3~2.5A
6V Operating voltages
Radial leaded devices.
Over-current protection
Very high voltage surge capabilities.
Available in lead-free version.
Fast time–to–trip
RoHS compliant, Lead- Free and Halogen-Free

Applications:

Over-current and over-temperature protection of automotive electronics
Hard disk drives
Point-of-sale (POS) equipment
PCMCIA cards
Power over Ethernet (POE)
HDMI 1.4 Source protection
Computers & peripherals
Industrial control
Security systems