Fusible Resistor or Fuse Resistor
what is a fusible resistor
The fusible resistor is a special type of resistor made for the purpose of the protection of any circuit. This resistor is made of such material that has characteristics of fusing without flames or without excess heat generation when the current load jumps suddenly more than required. When you see normally in any circuit this looks roughen and some Bigger in size and Not have Smoothness and Shining as the normal resistor. This resistor is always connected in series with the input main power supply to the circuit.
A fusible resistor is useful for highly sensitive circuits of lower power requirements and applications where the overload and surge handling requirements are not too severe. When any components of that circuit get faulty and change their behavior out of design property, then it may be there a fluctuation of current load change and like short circuit condition (not fully shorted) occur. In this situation, other components of the circuit can get damaged easily or even excess heat and flames destroy the whole system of the device. The fusible resistor provides a guarantee of the safety of the whole circuitry by Fuse itself quickly.
Generally, any fusible resistor manufactured of between very little value like 10Ω to 100Ω and these values used accordingly to the required circuit. Wirewound type fusible resistors are mostly used.
Difference between a fuse and a fusible resistor.
A fusible resistor acts as a safety fuse, but there is a difference between a fuse and a fusible resistor.
A normal glass tube fuse used where high surge current load devices used like 2A, 8A, 10A, etc and this will burn when high load occurs according to fuse capacity or when short connection.
The fusible resistor used in the circuit operates high voltage with small or lower currents such as 100ma, 250ma. A fusible resistor can pass the pulse of a high volt like 500v without failure, but it must fuse quickly without flames when 100v short circuit overloads.
Note – If any Fuse resistor Fused in any circuit – It denotes there is any fault in any component. Generally, in this case one or two components shorted by burnt. If you get shorted the fuse resistor through wire then the high risk of damage other components
So At First check, the other components of that circuit carefully and change before changing or shorted the fuse resistor. Because if any components did not get fully damaged but some of their property changed then also Fuse resistor will be fused again and again.