3. Electrical measurement techniques

3.1 DC current measurements

The insulating test piece can be regarded as a capacitor. When DC voltage is applied, a transient current first appears (known as the "absorption current", due to the various polarization phenomena – figure 1 ). After a period of time, which can be considerable, this current can tend towards an equilibrium value known as the "conduction current", i _c . Resistivity can then be calculated using this definition of conduction current.