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.

相应译文：

绝缘电阻R是与加在两电极板之间试样上的直流电电压及由此电压而产生的总电流相关的系数。两电极板是植入试样中或是与试样表面相连的。绝缘电阻是由材料的表面电阻和体积电阻决定的。直流电电压加在RESULTING CURRENT被测的之前的一个特定的时间段内。

测试步骤及方法在美国材料测试方法D257中的“直流电阻或绝缘材料电导”中有很详细的说明。应用此方法，用500伏的直流电电压加在试样上60秒，然后测得“RESULTING CURRENT”测试时间及电压随应用情况的不同而不同，但是为了做准确的对比加电压时间的长短与电压的大小一定要与特定的测试情况相一致。

有时测量试样的绝缘电阻是为了确定电路是否处于开路状态，如果是这样的话，开路状态的电阻值必须定义下来，比如，任何电阻值高于100 时，这条电路就很可能是开路。此时测量的准确与否是不重要的，此值是否高于某值是最重要的。

绝缘电阻测量的例子有：印刷电路板上印痕间的泄露电流的测量，以及多导体电缆内导体之间电阻的测量。