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C5TN01
2020.01.22
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PPTC RESETTABLE FUSE
How PPTC Resettable Fuse works
L
Point 3
Point 2
Point 4
Point 1
23OC
Resistance
Temperature
Typical PPTC
Operating Curve
125OC
Crystalline Polymer
Carbon Black Conductive Chain
Tripped
State
Temperature rise
during fault condition
Original
State
Temperature drops after
fault current removed
Molten Polymer
Epoxy Coating Solder Layer
Nickel Plated Copper Foil PTC Element
PPTC in Circuit
The typical PPTC application is to be used
as a series component in a circuit.
How It Works
Basic Structure
Our resettable fuses are designed band made of patented novel polymeric PTC material in thin chip form.
With electrodes and leads attached on both sides, it is placed in series to protect a circuit. At “normal
operating condition” the device remains at an extremely low resistance (milli-ohms) and allows the
electrical current to flow through it without any restriction. When over-current conditions occur, the
polymetic PTC material heats up and its resistance increases sharply. Such a sharp resistance increase
(to an insulated status) cuts off the current in the circuit, and consequently protects the element and device
in the circuit. Upon fault current being removed, the resettable fuse cools down and its resistance drops to
the original extremely low value. The resettable fuse is “reset” and allows the current flow through the
circuit again.