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Optical probe Electric Current Sensor: OpECS

BROCHURES
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  • ltra-small sensor head (Minimum Φ0.45mm)
  • Supports isolation current measurement
  • Wide Bandwidth DC ～ 150MHz
  • Measurable current ±140A
  • Available on oscilloscopes with 50Ω BNC input
BROCHURES
  • This product is regulated product subject to the foreign exchange and foreign trade control law of Japan.
    Export should not be allowed without appropriate governmental authorization.
About OpECS *

OpECS is an optical probe current sensor that enables current measurement by capturing the magnetic field generated around the current through the Faraday effect. When a magnetic field exists at the sensor head, the linearly polarized light is affected by the magnetic field and its oscillation direction changes. The direction of oscillation follows an elliptical orbit according to the direction of the magnetic field, and the change in direction is proportional to the magnitude of the magnetic field. The elliptically polarized light information is sent to the main unit (control unit) at the latter stage, where it is converted from an optical signal to an electrical signal. This signal can be input to an oscilloscope or other device equipped with a 50Ω-terminated BNC connector to measure the current.

Principle of Optical current Sensor

  • OpECS is a registered trademark of Citizen Watch Co., Ltd.

Sensitivity and measuring current range of OpECS

Positional relation between wire and sensor

Maximum sensitivity is obtained when the sensing element is in contact with the center of the wire, as shown in ① in the lower left figure. For the direction of the current flowing through the wire, a positive output is obtained when placed as in ①, and an inverted output is obtained when placed as in ②. When the sensor is away from the center of the wire as shown in ③, the magnetic field weakens and the sensitivity changes as shown in the lower right figure. Therefore, by maintaining the proper distance, it is possible to measure currents greater than the measurable current.

Wire diameter and sensitivity

linearity

If the distance between the center of the sire and the sensor is constant, the sensitivity does not change even if the wire diameter is changed, as shown in the figure below.

The linearity of the OpECS current sensor is ±1% and it is maintained up to ±140A.

Measurable current range

* Measured by contacting a Φ0.5mm copper wire