SMD fuse, as the name implies, the shape of the fuse is sticker-like, some people also call it square fuse. According to the fuse blowing speed response speed and so on, we generally divided into the following 4 types.
1. Slow-blow type/time delay type fuses.
2. Double alloy slow-blow type fuses.
3. Fast-response fuses.
4. Extra fast response fuses.
Slow blow fuses are ideal for circuits that contain momentary current surges or power-on surges. These circuits include: motors, transformers, incandescent lamps, and applicable load devices.
Fast-reacting fuses are fast-reacting and suitable for circuits without momentary current surges.
Special fast-response fuses are usually connected with silver. Because of their current limiting capability, these fuses are often used to protect semiconductor circuits.
Selection of the use of SMD fuses should pay attention to the following five details.
Size type: the size of the type should be based on the actual situation of the line, now the chip fuse is a lot of package size, such as 0402, 0603, 1206, 2410, etc..
Limit flow: in most resistive or semiconductor line load should use fast response fuse, but for inductive or capacitive load is to consider using ordinary or slow type fuse. Remember: the circuit itself is protected and not the fuse.
Installation location: Installation of the SMD fuse must be noted is never to connect the fuse to zero potential or ground line. The fuse should be connected to the fire line so that the line is immediately disconnected when the fuse blows, otherwise even if the ground is disconnected, the positive and negative voltage difference may still cause damage to the circuit.
Fuseholder: Using the correct fuseholder is as important as choosing the correct fuse. The fuse is a thermal component, so the fuse holder will greatly affect the speed of fuse blowing. Clamped fuse holder should pay attention to its contact point is good contact, bad contact point will produce contact resistance to make the fuse hot and affect the characteristics of the fuse, and too good heat dissipation will also affect the fusing speed of the SMD fuse.
Fuse replacement: be sure to change the same type of the same current value of the chip fuse. When the fuse blows must be a problem somewhere in the line, did not find the problem and casually replaced with a higher limit of the fuse may cause damage to the circuit.