Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

OCT

Symbols

Optical current sensor

An optical current sensor measures current from the rotation of polarised light in a fibre wound around the conductor, a magneto-optic effect proportional to the enclosed magnetic field. It is used in HV and DC applications where conventional CTs are bulky or where saturation and insulation are concerns.

Drawing use: SLD
Application: Metering & protection
Reference family: IEC / Manufacturer

A distinction that matters

An optical current sensor uses light in fibre; a conventional CT uses magnetic induction in a winding.

Full reference

Symbols

Rogowski coil current sensor

A Rogowski coil is wound on a non-magnetic former and placed around the conductor. Its output voltage is proportional to the rate of change of current, so an integrator in the relay or meter reconstructs the current waveform. With no iron core it does not saturate, which suits high fault currents and wide measuring ranges.

Drawing use: SLD / Schematic
Application: Metering & protection
Reference family: IEC / Manufacturer

A distinction that matters

A Rogowski coil has no iron core and gives a voltage output; a conventional CT has an iron core and a current output.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.