FOCS (Fiber-Optic Current Sensor) is very accurate, modular and easy to install. Another advantage is the isolation of the measuring part from the primary technology, which is sensed. Optical Fiber Current and Voltage Sensors is the first book to provide a complete, comprehensive and up to date treatment of the domain of fiber optic and polarimetric sensors, covering fundamental operating principles, characteristics, and construction. Utilizing a single-ended optical fiber wrapped around the current conductor, FOCS exploits the magneto-optic effect (Faraday effect). The FOCS can measure uni- or bi-directional DC currents up to 600 kA. Accurate measurement of electrical current in devices is a fundamental technology that is essential for controlling and monitoring the systems and equipment that many industries and our daily lives depend upon.