The non-intrusive measurement of a DC current is accomplished through the use of electronic sensors that use the Hall Effect to monitor and measure electrical currents.

### What is the Hall Effect

The Hall Effect is the principle that a magnetic field applied perpendicular to a current will create a proportional Hall voltage perpendicular to the two fields. In a typical application, the DC current in the primary conductor creates the magnetic field which is proportional to the amount of DC current flowing through the conductor.

This magnetic field acts on a current flowing through the Hall Effect sensor resulting in a Hall voltage proportional to the primary conductor DC current. This technology allows non-intrusive DC current and DC pulse measurements.

### Open Loop Sensor

The basic Hall Effect electronic sensor is configured as an “*open-loop*” sensor. It measures the Hall voltage to determine the primary conductor DC current. For example, see our open-loop Hall Effect sensor: HOS-Q11 Open-loop Hall Effect Sensor

### Closed Loop Sensor

A “*closed-loop*” sensor configuration is a more accurate Hall Effect electronic sensor. The “*closed-loop*” design incorporates a second magnetic field, which is used to offset the primary conductor magnetic field. The amount of power necessary to zero out the primary conductor field is then the representation of the DC primary conductor current. The zeroing of the magnetic flux provides a highly accurate representation of the primary conductor current. For example, see our closed-loop Hall Effect sensor: HCS-C5 Closed-loop Hall Effect Sensor

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