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Insulation Resistance Measurements

Insulation resistance, R , is the ratio of a DC applied voltage to a specimen between two electrodes and the total current between them, The two electrodes are either embedded into or in contact with the specimen. The insulation resistance is dependent on both the surface and volume resistance of the material. The DC voltage is applied for a specified period of time before the resulting current is measured.

This test procedure is described in detail in the American Society for Testing Materials method D257 entitled, “DC resistance or Conductance of Insulation Materials.” According to this procedure, an applied voltage of 500V is applied for 60 seconds and then the resulting current is measured. This time and voltage often varies depending upon the application but must always be consistent to a specific test in order to make accurate comparisons.

Sometimes the insulation resistance of a sample is measured only to determine if it is an open circuit. If this is the case, the value of what is considered to be an open circuit must be defined. For example, any resistance value above 100G  may be considered an open circuit,The accurate comparisons.

Examples of insulation resistance measurements include measuring the leakage between traces on a printed circuit board or the resistance between conductors in a multiconductor cable.

相應譯文：

絕緣電阻R是與加在兩電極板之間試樣上的直流電電壓及由此電壓而產(chǎn)生的總電流相關的系數(shù)。兩電極板是植入試樣中或是與試樣表面相連的。絕緣電阻是由材料的表面電阻和體積電阻決定的。直流電電壓加在RESULTING CURRENT被測的之前的一個特定的時間段內(nèi)。

測試步驟及方法在美國材料測試方法D257中的“直流電阻或絕緣材料電導”中有很詳細的說明。應用此方法，用500伏的直流電電壓加在試樣上60秒，然后測得“RESULTING CURRENT”測試時間及電壓隨應用情況的不同而不同，但是為了做準確的對比加電壓時間的長短與電壓的大小一定要與特定的測試情況相一致。

有時測量試樣的絕緣電阻是為了確定電路是否處于開路狀態(tài)，如果是這樣的話，開路狀態(tài)的電阻值必須定義下來，比如，任何電阻值高于100 時，這條電路就很可能是開路。此時測量的準確與否是不重要的，此值是否高于某值是最重要的。

絕緣電阻測量的例子有：印刷電路板上印痕間的泄露電流的測量，以及多導體電纜內(nèi)導體之間電阻的測量。