How to Apply PTC Thermistor in LED Tube Short Circuit Design

The latest discovery that PTC(Positive Temperature Coefficient)，one kind of positive temperature coefficient thermistor, can be applied in LED tube short circuit design.

PTC is one typical semiconductor resistance of temperature sensitiveness. Beyond the Curie Temperature, its resistance value will increase by steps 

LED Tube shortcut circuit design was previously realized by short circuit chip:

                                                   (Picture Courtesy of SYHDEE)

One big disadvantage of which, is that once the wiring mistake occurs, it might cause circuit short-cut and electronic components damage. Replacing short cut chip with PTC can solve this problem:

                                                    (Picture Courtesy of SYHDEE)

PTC should be wired in series in circuit while LED tube works. Under normal circumstances, PTC resistance value is small and so is energy loss, thus affecting little the normal working. Whereas overcurrent happens, temperature of PTC thermistor will rise up rapidly and so does PTC resistance value, automatically setting up overcurrent protection circuit. When faults removes, the power supply will be auto recovered.