Littelfuse PTC (resettable fuse) technology utilizes a unique Lead-Free polymer-based, Positive Temperature Coefficient (PTC) material to protect electrical circuits from overcurrent conditions. During normal operation, numerous carbon paths within the polymer allow the device to conduct electricity. As current through the PTC (resettable fuse) reaches its rated threshold, the polymer material begins to heat causing the polymer to expand. The resulting expansion breaks the carbon chains to reduce the current through the circuit to a small leakage current. The increased resistance in the resettable fuse works to protect circuitry by limiting potentially damaging current. When the fault (overcurrent) is removed from the circuit, the PTC (resettable fuse) will reset itself thereby allowing current to flow through the circuit again
Littelfuse offers a full range of surface mount and radial leaded PTC (resettable fuse) products. Designed for "plug and play" applications, the 1206L and 1812L surface mount PTC (resettable fuse) series provide protection for electronic circuits from overcurrent conditions in a wide range of "plug and play" applications. Littelfuse surface mount PTCs comply with electronic industry standards for lead reduction. The 30R and 60R series radial PTCs are rated at 30VDC and 60VDC respectively, and are designed for use in higher voltage applications that require minimal maintenance and are subject to repetitive overcurrent conditions. Applications include industrial controls and home security systems. All Littelfuse PTC (resettable fuse) series are recognized under the Components Program of Underwriters Laboratory, the Component Acceptance Program of CSA, and TUV. All specifications for all five PTC (resettable fuse) series are available on our website for review.
There is an important area of applications where the use of resettable fuses (PTCs) is becoming a requirement. Much of the design work for personal computers and peripheral devices is strongly influenced by the Microsoft and Intel System Design Guide which states that "Using a fuse that must be replaced each time an overcurrent condition occurs is unacceptable." And the SCSI (Small Computer Systems Interface) Standard for this large market includes a statement that "....a Positive Temperature Coefficient device must be used instead of a fuse, to limit the maximum amount of current sourced".
When to apply a resettable fuse vs. a traditional fuse is always the choice of the designer or technician. The decision should be based on the overall project. In some cases the benefits of a PTC (resettable fuse) are significant. Be assured that a PTC (resettable fuse) from Littelfuse will be of the highest quality and when used appropriately, will provide outstanding protection from a potentially hazardous overcurrent event. To find out more about when you should choose PTC (resettable fuse) technology or a fuse, click here: Knowledgebase: Fuses vs. PTCs.
Additional Information:
Fuse vs. PTC (Resettable Fuse)
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Fuses
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