Metal oxide varistor (MOV) is a semiconductor element with unique grain boundary structure. Its resistance value decreases sharply with the increase of voltage. It has the advantages of excellent nonlinear volt-ampere characteristics, high current capacity, low residual voltage, no freewheeling and low cost. It has been preferred to be used in power supply and signal port as over-voltage protection components.

  Although the current capacity of the MOV itself is large, the energy capacity is not large, that is, its rated continuous power is very small. The commonly used MOV rated power is generally at the mW level, which cannot withstand the constant current. For example, when MOV runs in U=53V circuit, the leakage current is 100μA due to aging. According to P=UI, substituting U=53V and I=100μA, the calculated heating power consumption is 5.3mW, which is the same level as the power of MOV itself. When the MOV leakage current reaches the milliampere level, it is enough to exceed the continuous power that it can withstand, which will cause combustion problems. To the burning problem caused by the failure of MOV, the current mainstream industry adopts the blocking method, which has many shortcomings and cannot achieve the purpose of truly solving the burning problem of MOV. The latest research technology adopts sparse methods to prevent and deal with warnings in advance, so as to truly eliminate the burning problem of MOV. At present, Anhui Jinli conducts in-depth experimental research on two aspects of abnormal temperature and abnormal leakage current.