How does a fuse resistor work?

What is a fuse resistor? What is its working principle? Before we understand the working principle of a fuse resistor in depth, let us briefly learn what a fuse resistor is? In fact, a fuse resistor is a resistor and a fuse. It is a special component with dual functions. It is usually used in circuits to protect load circuits or power circuits.

According to the recoverability characteristics, fuse resistors can be divided into recoverable and disposable ones. As for recoverability, it is well known that it will fuse when overcurrent, short circuit and other phenomena occur, but it can self-recover after a certain period of time. Disposable means that it cannot be restored after it breaks. If you want to reuse it, you can only buy a new one.

Application Scenarios Next, let’s talk about its application scenarios. Fuse resistors are usually used in integrated circuits, larger power transistors or the back end of power supply outputs. These circuits have a common characteristic, that is, once the downstream circuit encounters High current will bring inevitable losses to the system, so a fuse resistor must be added to the front stage.

How to use Finally, let’s explain how to use it. As shown in the figure below, R1 is the fuse resistor. It connects the power output of the front stage and the load circuit of the subsequent stage. When a short circuit occurs in the subsequent stage circuit, the resistance of the load circuit The value will be close to zero, and because the resistance of the fuse resistor is very small, only about a few ohms, the current flowing through R1 will rise sharply, causing R1 to be blown. After R1 is fused, the front-end power supply and the rear-end load are in an open circuit state, thereby protecting the load.

Application principle of fuse resistor

When making a film fuse resistor, the local thread pitch of the film layer is usually shortened or the surface of the film layer is coated with low melting point glass slurry (or a mixture of glass powder and metal oxide, etc.). When the film fuse resistor passes through When the operating current is too large, the conductive film layer of the resistor will melt quickly. And because the casing of the fuse resistor is usually made of ceramics, silicone resin, flame retardant paint and other materials, it can effectively prevent combustion and other effects when the fuse is blown. The above is an analysis of the working principle of the fuse resistor, I hope it can inspire you.