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The electrical load of the resistor has those effects on the resistor!
Apr 23, 2018

The electrical load of the resistor has those effects on the resistor!


The conductive film layer of the resistor is generally obtained by a vapor deposition method, and an amorphous structure exists to some extent. From the thermodynamic point of view, there are crystallization trends in amorphous structures. Under working conditions or environmental conditions, the amorphous structure in the conductive film layer tends to crystallize at a certain speed, that is, the internal structure of the conductive material tends to be densified, which can often cause a decrease in the resistance value. The crystallization speed increases as the temperature increases.

Electric load high-temperature aging: In any case, the electric load will accelerate the aging process of the resistor, and the effect of the electric load on accelerating the aging of the resistor is more pronounced than the accelerated aging of the elevated temperature because of the temperature of the contact portion of the resistor body and the lead cap. The rise exceeded the average temperature rise of the resistor body. Generally, the life is shortened by half every 10°C. If the overload causes the temperature of the resistor to rise by more than 50°C above the rated load, the life of the resistor is only 1/32 of the normal life. Accelerated life testing can be performed in less than four months to evaluate the stability of the resistor during 10 years


DC load electrolysis: under the action of DC load, electrolysis causes resistors to age. The electrolysis occurs in the groove resistor groove, and the alkali metal ions contained in the resistor matrix are displaced in the electric field between the grooves to generate ion current. In the presence of moisture, the electrolysis process is more severe.

If the resistive film is a carbon film or a metal film, it is mainly electrolytically oxidized; if the resistive film is a metal oxide film, it is mainly electrolytically reduced. For high-resistance thin-film resistors, the consequences of electrolytic action can increase the resistance, and film damage can occur along one side of the spiral. Conducting a DC load test in a hot-humid environment can provide a comprehensive assessment of the antioxidant or anti-reducing properties of the resistor substrate material and film, as well as the moisture resistance of the protective layer.