Fast break (fuse) chip fuse used for circuit boards or special equipment as long as the current more than the current rating of the fuse, can only be used for short circuit protection.
A slow - blown fuse is also called a delay - chip fuse, which is shown to be in good condition and can provide protection for long periods of time when the circuit appears to be in good condition. Some circuit several times greater than the normal operating current in the current switching moment, although the peak current is very high, but it occurs in a very short time, we call it the pulse current has called it the impact of current or called surge current. Fuse is common to bear this current, so the circuit if using common fuse would not boot, fuse if the use of a larger size, so when the circuit overload and lack of protection. The melt of the time delay chip fuse is processed by special processing, which has the function of absorbing energy, and the energy absorption quantity can be adjusted so that it can resist the impact current and can provide protection to the overload. The main difference between the slow and fast fuse fuse fuse is its instant pulse current capacity, which means that it can resist the impact of surge current when the switch without action, so as to ensure the normal operation of the device, so the slow fuse type fuse is often called surge resistant fuse. Technically, the slow fuse fuse has a larger value of I2t melting heat energy, the energy needed to fuse fuse is large, so for the same rated current of the fuse, fuse faster than the slow fuse high pulse ability a lot.
Because of the slow fuse fuse I2t is larger than the same size fast fuse fuse, the fuse time so happened when the current in the circuit will be slower than the fast fuse, it will not like the protection performance of some people are worried about the poor? We say no! Because once the circuit failure, over current will not disappear, sustained current energy will greatly exceed the fuse I2t, no matter what the fuse will be a fuse, fuse and fuse between the slow fast time difference is very important for the protection requirements, only in the protected circuit in sensitive device the need to protect the case, will have an impact on the slow fuse protection performance.
Because of these differences, the slow and fast fuse fuse fuse fuse will be applied in different circuit: pure resistance circuit (with little or no surge) or circuit to protect IC sensitive devices must use expensive fast fuse fuse; and capacitive or inductive circuit (switch when surge) the input / output power, the best part of the slow fuse fuse circuit protection; in addition to IC, most of the use of fast fusing fuse occasions are able to switch to a slow fuse fuse, to improve anti-interference ability; and in the use of slow blow fuse. If the switch to quickly fuse fuse, will often result in the boot the fuse cannot work normally phenomenon.
In addition, due to the low cost of the slow fuse chip fuse fuse fuse fuse to be much higher than the fuse, economic considerations have become an indirect factor in the selection.


From the electronic related article:

　　Judgment and treatment principle of fuse fuse fuse in the role

　　How to choose the correct placement of the fuse, the patch self recovery fuse selection of important factors