PTC Resettable Fuses

TR600-150F-EX is a PTC Resettable Fuse, which refers to either a polymeric or ceramic Positive Temperature Coefficient fuse which is "resettable" in the sense that it will open circuit at an overcurrent condition, trip current to take the input voltage and current of the circuit, and then reset after the overcurrent has been removed. This type of fuse is often used as protection in automotive applications, such as those which contain critical safety elements such as airbags, anti-lock brakes and navigation systems.

Application

The TR600-150F-EX is suitable for a wide range of applications in many industries. For automotive and mobile applications, it is most commonly used to provide short-circuit current protection for components and wiring harnesses. In the industrial market, these fuses are used in appliances, office equipment and medical electronics. They are also used in automotive and consumer electronics to provide overvoltage protection for sensitive components, such as integrated circuit devices. Additionally, they are used for secondary protection in many consumer electronics products, fusing power and signal lines from components, such as monitors and printers.

Working Principle

When an overcurrent occurs, the PTC Resettable Fuse will trip, interrupting the supply of electricity. When the overcurrent is removed, the device will reset itself in a matter of seconds and become conductive again. TR600-150F-EX works on the principle of heat generation due to the resistance of the element. When the current flowing in the element increases, the wattage generated also increases, causing a rise in temperature of the element. The higher the temperature, the higher the resistance of the element, thus the flow of current reduces, and the device trips. The amount of current at which the fuse trips is adjustable, by changing the component values. The current rating of the fuse is determined by the size of the element, the cut-off settings of the device, and the surrounding ambient temperature.

Materials and Construction

The PTC resettable fuses are made up of two terminals, one which is copper plated steel, and one which is either copper or nickel-plated steel. The element is constructed using a Ceramic Core which is enclosed in a polymeric sleeve. The core consists of a perforated copper tube containing a thin granular ceramic material, which is impregnated with a thermally conductive paste.

Advantages

PTC resettable fuses have many advantages over traditional fuses, such as they can be used in higher temperature applications, they have fast response times, are easy to install and provide multiple levels of protection. They are also safer than ordinary fuses, since they will not blow if there is a minor overcurrent. Lastly, they are smaller in size than a traditional fuse, and therefore less intrusive in high density layouts.

Disadvantages

As with all components, there are also some disadvantages to using PTC resettable fuses. In comparison to traditional fuses, they are more expensive, and the current ratings are not as precise as if on a fuse. Additionally, they can wear out during long term overloads, which a traditional fuse would not.

TR600-150	Littelfuse I...	0.0 $	1000	PTC RESET FUSE 60V 150MA ...
TR600-150-RA-B-0.5	Littelfuse I...	0.37 $	1000	PTC RESET FUSE RADIALPoly...
TR600-150QF-EX-B-0.5	Littelfuse I...	0.88 $	556	PTC RESET FUSE RADIALPoly...
TR600-150F-EX	Littelfuse I...	0.74 $	1295	PTC RESET FUSE 250V 150MA...
TR600-150F-EX-2	Littelfuse I...	--	7800	PTC RESET FUSE 250V 150MA...
TR600-150F-EX-RB	Littelfuse I...	1.04 $	1000	TR600-150F-EX-RB
TR600-150QF-EX-R1-B-0.5-1	Littelfuse I...	0.39 $	1000	TR600-150QF-EX-R1-B-0.5-1