The laser power density and the temperature of post heat processing have great effect on the sheetresistivity and TCR of PTC thermistor, and there exist optimum values for these parameters.
激光功率密度和后续热处理温度对PT C热敏电阻方阻和电阻温度系数影响较大，并都存在一个最佳值。
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In this article, we drive the equations of measuring resistivity and surface sheet resistance, taking into account the contact dimension and putting the location of the four probes arbitrary.