Patent ID: 6218825
Filing Date: 2001-04-17
Classification: G01R

Abstract:
A current, comprising:a magnetic core having a primary winding in which a current that is to be measured flows, and having at least one secondary winding;an alternating current that is generated by a free-running generator circuit that is fed to the secondary winding, which current saturates the magnetic core in alternating fashion in at least one direction;a polarity of the alternating current that is generated by the generator circuit varying as a function of current flowing in the secondary winding and as a function of at least one threshold value for this current;the generator circuit having a series circuit of first and second inverting amplifiers, the secondary winding being connected between input and output of the first amplifier, and the input of the first amplifier also coupled with an output of the second amplifier via a first resistor, and a pulsewidth-modulated output signal, which corresponds to the current to be measured, being tappable at the output of at least one of the first and second amplifiers.