In summary, a ceramic PTC Thermistor is a temperature-sensitive resistive device whose resistance increases sharply above its trip current and protects circuits from over current damage. Murata’s PRG (surface mount package) and PTGL (leaded package) series offer a wide range of protective operating currents, from 10 mA to 1.5 A. The surface mount PRG series effectively works to protect IC against circuit failures. It can also work as a small chip resistor, incorporating self protection as well.  Finally, leaded type PTGL series works in higher current circuits. It can provide motor lockup protection, LED protection, and protection in various power supply applications.