Abstract: A current measurement device is configured to measure electrical current in a primary conductor that is electrically insulated from the current measuring device. The current measuring device includes a transformer with a saturable magnetic core formed with a central aperture and a current measuring circuit. The electrical conductor in which electrical current is to be measured is disposed in the central aperture of the magnetic core. The current measuring circuit includes a current source driven by a voltage ramp generator that is connected to the secondary winding in a direction opposite the flow of electrical current in the primary conductor. When the magnetic flux in the transformer core is equal and opposite the magnetic flux generated as a result of the electrical current flowing in the primary conductor, the voltage of the voltage ramp generator is representative of the DC or AC electrical current flowing in the primary conductor.

Abstract: A current measurement device is disclosed that is configured to measure electrical current, both AC and DC, in a primary conductor that is electrically insulated from the current measuring device. Unlike known current measuring devices, the current measuring device in accordance with the present invention does not utilize a Hall effect device and is more accurate and less expensive than current measuring devices employing such Hall effect devices. The current measuring device in accordance with the present invention includes a transformer with a saturable magnetic core formed with a central aperture and a current measuring circuit. In one embodiment of the invention, the transformer is provided with a secondary winding and no primary winding. The electrical conductor, i.e. primary conductor, in which electrical current is to be measured is disposed in the central aperture of the magnetic core and thus acts as a primary winding having a single turn.