Cầu chì chip có thể tái định cư là gì?

A resettable chip fuse, also known as a PTC (Hệ số nhiệt độ dương) resettable fuse, is a type of surface mount device (SMD) 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, cho phép dòng điện chạy trở lại.

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

SMD cầu chì tái định cư 1812 16V 2A Chip Mount Surface để bảo vệ quá dòng của Com-Communication

Cầu chì chip có thể đặt lại (PPTC) là một yếu tố bảo vệ quá dòng dựa trên các đặc điểm hệ số nhiệt độ dương của polymer. Nó có chức năng đặt lại tự động và được sử dụng rộng rãi trong việc bảo vệ mạch thiết bị điện tử. Sau đây là những điểm cốt lõi của nó:

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). Under normal conditions, 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) vật liệu. This material exhibits a significant increase in resistance as temperature rises.

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LF 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

Bảo vệ quá dòng:
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.

Tự động đặt lại:
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.

Bảo vệ quá dòng:
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, Điện thoại di động, Thiết bị y tế, and automotive electronics.

Example:
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.