Patent ID: 7541799

Claim:
A method for measuring a current flowing in an electrical conductor with a sensor disposed in the region of the electrical conductor for measuring a magnetic field surrounding the electrical conductor, whereby the sensor comprises a magnetic circuit having a first and a second section and a magnetizing device for magnetic saturation of the second section, the method comprising: measuring the magnetic field after switching off a positive saturation of the second section to define a first measured magnetic field value B(P 1 ); measuring the magnetic field after switching off a negative saturation of the second section to define a second measured magnetic field value B(P 2 ); calculating a first mean switched off magnetic field value B(P 0 ) by averaging the first measured magnetic field value B(P 1 ) and the second measured magnetic field value B(P 2 ); measuring the magnetic field after switching on a positive saturation of the second section to define a fourth measured magnetic field value B(P 4 +); measuring the magnetic field after switching on a negative saturation of the second section to define a fifth measured magnetic field value B(P 4 −); calculating a second mean switched on magnetic field value B(P 4 ) by averaging the fourth measured magnetic field value B(P 4 +) and the fifth measured magnetic field value B(P 4 −); and calculating a current flowing through the electrical conductor by subtracting the second mean switched on magnetic field value B(P 4 ) from the first mean switched off magnetic field value B(P 0 ) and multiplying a resulting difference by a constant.