ABSTRACT
The basic parameters of any sensor are linearity, offset (for dc sensors) and sensitivity, and also stability of offset and sensitivity with temperature and time. Also important is the sensor bandwidth (or frequency characteristics), as current waveforms often contain high-frequency component. The most common way to achieve geometrical selectivity is to use a closed magnetic circuit with a measured conductor inside. This is used in current transformers, fluxgate current sensors, and in most Hall current sensors. Optical current sensors have several advantages that are very attractive for power distribution applications. Most optical current sensors are based on the Faraday effect—either in bulk material or in an optical fiber. Magneto-optical point sensors (or unlinked sensors) use a piece of glass or a crystal rod placed in the neighborhood of the electric conductor. The sensor is usually interrogated by optical fibers. Current clamps usually have an openable magnetic yoke, so they can be mounted without interrupting the measured conductor.
