APPARATUS FOR AND METHOD OF CORRECTING FOR A GAIN ERROR RESULTING FROM THE POSITION OF A POLE OR ZERO IN A TRANSFER FUNCTION AND TO A CURRENT MEASUREMENT DEVICE INCLUDING SUCH AN APPARATUS

摘要

The response of a Rogowski coil based current measuring circuit is often proportional to frequency. To correct for this a low pass or integrating function is applied to the response to linearize it. The low pass filter is made from real resistors and capacitors, and tolerances in their values significantly affect the estimate of current. This disclosure relates to a way of addressing such problems. This allows consumers of electricity to have confidence in the accuracy of, for example, their electricity meter.