SMD fuse is a miniature fuse, which is usually connected in series in the circuit, when the circuit malfunction reaches or exceeds the value of the melting current, to protect the electronic components of electrical appliances.

First, the SMD fuse has positive and negative pole?

SMD fuse is a kind of thermal fuse, it plays a role in overheating protection, and there is no positive and negative points, it is no polarity. On the chip fuse will only mark a few amperes of current and a few hundred volts of voltage. For example, 2A/250V, it means that this SMD fuse can work within 250V voltage and 2A current, if it exceeds this condition, the SMD fuse will be blown. So we should pay attention to these two indicators when we use SMD fuses.

Second, what are the SMD fuse models

SMD fuses in the small fuse industry is a relatively high technology content of the new varieties, with a small size, easy to install, small space and other advantages.

SMD fuses can be divided into SMD current fuses and SMD self-recovery fuses. It can also be divided into disposable SMD fuses and patch self-recovery fuses, disposable fuses need to be replaced after the protection, self-recovery fuses can be reused after the protection of power failure. SMD self-recovery fuses can be categorized by size: 0402, 0603, 1206, 1812, 2920, etc..

SMD fuses can be divided into the following basic types: slow blow type / time delay type fuses, double alloy slow blow type fuses, fast response type fuses, special fast response fuses.

Slow blow fuses are ideally suited for circuits containing instantaneous current surges or start-up surges. These circuits include: motors, transformers, incandescent lamps and applicable load devices. Fast-acting fuses are fast-acting and are suitable for circuits that do not have an instantaneous current surge. Fast-acting fuses usually have silver connections. These fuses are often used to protect semiconductor circuits due to their current limiting ability.