Measurement of extremely high insulation resistances - has amplifier, voltage source controlled by program and controllable picoammeter with negative feedback

摘要

The resistances lie in the giga or teraohm range. A voltage source controlled by the program, and a controllable picoammeter with a negative feed-back circuit and amplifier are used. A contact (Z) operated by the program control (S) shorts out the amplifier (-V) negative feed-back circuit of the picoammeter (P) at the beginning of each measurement. The voltage source (U) is connected when the feed-back circuit is short-circuited. After all capacitances (Cq, Cx) in the input circuit and in the measured resistance are charged, the shorting contact (Z) is opened. Then an analogue or digitally operating transient attachment (E) is connected to the feedback circuit through an input capacitor (Ce). Controlled by the program control, it applies a booster voltage for the rest of the transient period.