Piezoresistor with heat protection function

Abstract

The invention is a varistor with thermal protection function, which comprises a body. One side of the body is equipped with an insulation washer, and a through hole is positioned on the insulation washer. A first conductive pin is positioned at the other side of the body, and a second conductive pin is positioned on the insulation washer. A heating fuse is positioned on the insulation washer, oneend of the heating fuse and the second conductive pin form the electrical connection, and the other end and the body form the electrical connection by the through hole of the insulation washer. When the body of the varisor bears the continuous overvoltage to cause the overheat condition, due to the only end contact between the heating fuse and the second electrode, the heating fuse can rapidly melt and crack to form the open circuit for preventing the electronic module of the current circuit from being damaged, furthermore the isolation of the insulation washer can effectively separate the heating fuse and the second electrode after melting for preventing from the communication again.

Description

technical field [0001] The invention relates to a varistor with thermal protection function, especially a self-failure protection function, which has a self-protection function when various types of overvoltage cause the temperature of the varistor body to rise abnormally and fail. the varistor. Background technique [0002] Due to its superior nonlinear volt-ampere characteristics, varistors are widely used in overvoltage protection and surge absorption components of lines, equipment and components. Regardless of whether varistors are used in power lines or electronic circuits, if various types of instantaneous If overvoltage occurs frequently, the varistor will operate frequently to suppress the increase in overvoltage and absorb and release surge energy to protect electrical equipment and components. If things go on like this, the performance of the varistor will deteriorate or even fail in the long run. [0003] Furthermore, when the piezoresistor is subjected to contin...

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Problems solved by technology

[0004] However, when the thermal fuse used as an overheat protection structure in the varistor with thermal protection function of the prior art shrinks due to overheating and forms an open circuit, it is easy to cause the thermal fuse to fail to continue due to the energy not being continuously conducted to the thermal fuse. Shrink to form a path again, so the response speed of the thermal fuse in the prior art is too slow to sense the high temperature in time and break the circuit in time, or the ability to withstand the impact of large current is weak and easy to fail, so the thermal fuse in the prior art The thermal protection features of fail-safe varistors still have their drawbacks

[0005] Furthermore, the varistors with thermal protection function in the prior art generally package the thermal fuse and the varistor itself together, and when the thermal fuse overheats and shrinks to form an open circuit, the generated gas expands or trips The sparks generated will destroy the outer sealant and cause the internal components of the varistor to spray outwards and affect other components in the current loop. In the device, such as household appliances, 3C electronic products, etc., the sudden loud noise will frighten the user

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