什麼是可重複的芯片保險絲?

A resettable chip fuse, also known as a PTC (正溫度係數) resettable fuse, is a type of surface mount device (貼片式) that protects electronic circuits from overcurrent and overheating. It acts like a traditional fuse but can automatically reset itself after a fault is cleared. When a fault like an overcurrent or short circuit occurs, the fuse’s resistance increases, limiting the current flow. Once the fault is removed and the fuse cools down, its resistance returns to normal, 允許電流再次流動.

PPTC chip self recovery fuse 1210 2A 2.5A 3A 6V 30V 33V 60V SMD

Resettable SMD Fuse 1206 SMD Chip 6V 0.35A (e0113 4c5f1 48d2a d4c5b 1f85e d0afa

SMD保險絲可重新安置 1812 16V 2A表面安裝芯片用於com通信過度保護

可重複的芯片保險絲 (PPTC) 是基於聚合物的陽性溫度係數特性的過電流保護元件. 它具有自動重置功能，可廣泛用於電子設備的電路保護. 以下是其核心點:

1. Structure and working principle
‌Material composition‌
It is composed of a specially treated polymer resin (such as PE polymer) and conductive particles (carbon black or metal particles). 正常情況下, the conductive particles form a low-resistance path (0.1-several ohms)‌‌.
‌Protection Mechanism‌
When overcurrent occurs, the thermal effect of the current causes the resin to melt and expand, the conductive network breaks, and the resistance suddenly increases to a high resistance state (up to the megohm level), limiting the current to the microampere level‌.
After the fault is resolved, the conductive particles cool and shrink, reconnect, and return to a low resistance state, without the need for manual replacement‌.
PTC Behavior:
Resettable fuses utilize a Polymeric Positive Temperature Coefficient (PPTC) 材料. This material exhibits a significant increase in resistance as temperature rises.

Littelfuse Surface Mount Resettable Fuse China Supplier

低頻 1812 Resettable Fuse PPTC 1812L SMD Self-Recovery 0.2A 0.5A 500mA 0.75A 1.1A 1.5A 2A 2.6A 3A 6V 8V 13.2V 15V 24V 30V

Overcurrent Protection Surface Mount PPTC Resettable Fuse 6V 30V 33V 60V SMD

過流保護:
When a current exceeds the fuse’s rated value flows, the PPTC material heats up, causing its resistance to increase. This increase in resistance reduces the current flow, preventing damage to the circuit.

自動復位:
Once the fault is removed and the fuse cools down, the resistance decreases, allowing normal current flow to resume.

Key Features and Benefits:
Self-Resetting:
The ability to automatically reset after a fault event makes it a reusable alternative to traditional fuses.

過流保護:
Protects circuits from damage caused by excessive current, short circuits, or overheating.

Space-Saving:
SMD packaging allows for integration into compact electronic devices.
Wide Range of Applications:
Found in various devices, including computers, 智慧型手機, 醫療設備, and automotive electronics.

例子:
Imagine a situation where a USB port on a laptop is accidentally short-circuited. A resettable fuse on the USB power line would detect the overcurrent and increase its resistance, limiting the current and preventing damage to the laptop’s power supply and other components. Once the short is removed, the fuse would reset, and the USB port would be ready to use again.