In many circuits, we often encounter great harm caused by overvoltage, surge, overheating and so on. The latest circuit protection devices not only need to pay attention to volt-ampere characteristics, protection level and other factors, but also consider many other problems. As electronic devices are becoming increasingly thinner, smaller resistive components have to be developed to meet size limits so as to cover a smaller footprint. This requires manufacturers to continuously improve the energy density of resistance components. When the interface rate of electronic equipment is constantly increasing, we must consider the size of the capacitance of the protection device in order to ensure signal integrity. And the protection scheme must follow the trend of interface development. Meanwhile, impact resistance times, anti-seismic, moisture-proof should be also guaranteed.

Although there are many kinds of protection devices, they can be divided into over-current protection and over-voltage protection. Resistor is one of the most common circuit protection components. The most important overcurrent protection device is the fuse, also known as fuse resistance. It is generally in series in the circuit, requires its resistance to be small (low power consumption), when the circuit is working normally, it is only equivalent to a wire, can be a long time stable conduction circuit. Due to the power supply or external interference caused by the current fluctuation, it should also be able to withstand a certain range of overload. Only when there is a large overload current (fault or short circuit) in the circuit, the fuse resistance will act, by breaking the current to protect the safety of the circuit, in order to avoid the danger of product burning.

In the process of interrupting the circuit of the resistor, because of the existence of the circuit voltage, the arc will occur at the moment of the melt breaking. High-quality fuse should avoid this kind of flying arc as far as possible. After breaking the circuit, the resistor should be able to withstand the voltage applied to both ends of the circuit. The resistor damaged by pulse will gradually reduce the ability to withstand the pulse, it is necessary to consider the necessary safety allowance when selecting.


Therefore, it is necessary to pay attention to its resistance characteristics and the basic conditions of rated current. In addition, surrounding environment should be taken into consideration when installing, the resistor will not work until it reaches its maximum bearing current. At present, many circuits are speeding up the use of resistors, more and more protection circuits are added to the high-precision resistor products to provide the security of resistors.