In summary, Multifuse® polymer PTCs from Bourns offer either overcurrent or over temperature protection for electrical circuitry. If a fault condition occurs, the Multifuse® device will heat due to I2R losses causing the resistance to rise dramatically and allowing only a trickle current flow to the circuit, thus protecting it. All that is needed to reset the Multifuse® after the fault condition has cleared is to cycle power to the system, eliminating the need for service calls to replace blown fuses. Also, the PSMF series is available in a size and rating ideal for portable handheld applications.