The working principle of PPTC（Polymeric Positive Temperature Coefficient） is based on the positive temperature coefficient property of the material. At normal operating temperature, the material of the fuse is in a low-resistance state; once the current exceeds the rated value, the internal temperature of the fuse rises, causing the material to be in a high-resistance state, limiting the flow of current and preventing equipment damage or fire caused by overcurrent. But once the current drops to a safe value range, the internal temperature of the fuse drops, and the material assumes a low-resistance state again, returning to a normal energized state.
The application precautions of PPTC resettable fuse are as follows:
1. Fully understand the working conditions of the protected circuit, and choose the appropriate rated voltage and current value of the fuse.
2. Avoid damage to the fuse by mechanical or other physical factors, resulting in failure or self-recovery.
3. During the installation process, avoid the fuse being in a high temperature environment or subject to excessive vibration, so as to prevent the fuse from failing early or being disturbed from self-recovery.
4. For the fuse that needs to be replaced, a fuse with the same specification and performance must be selected for replacement.
5. For circuit equipment that is not commonly used, the status and function of the fuse should be checked regularly to ensure that it can work normally when needed.
