What is ampere per meter (A/m, Oe, oersted)? - Definition from WhatIs.com


ampere per meter (A/m, Oe, oersted)

Part of the Smart grid glossary:

The ampere per meter (symbolized A/m) is the International Unit of magnetic field strength. It is derived from basic standard units, but is expressed directly in base units and cannot be further reduced.

Consider the interior of a long, cylindrical coil with a single winding and an air core. Suppose that the linear current density in this coil is 1 ampere per meter of displacement as measured along the coil axis. (This expression differs from current density per unit area, which is expressed in amperes per meter squared .) Then the magnetic field strength in the interior of the coil is defined as 1 A/m.

ampere per meter illustration

For a given coil, the magnetic field strength is directly proportional to the linear current density. Thus, if the linear current density doubles, so does the magnetic field strength; if the linear current density becomes 1/10 as great, the magnetic field strength also diminishes by a factor of 10.

Sometimes, magnetic field strength is expressed in units called oersteds (symbolized Oe). The oersted is a larger unit than the ampere per meter. Approximate conversions are:

1 Oe = 79.578 A/m
1 A/m = 0.012566 Oe

Also see ampere , current , magnetic field , meter , and International System of Units ( SI ).

This was last updated in February 2011
Posted by: Margaret Rouse

Related Terms


  • intranet of things

    - An intranet of things is, depending on your viewpoint, either an element of the all-encompassing Internet of Things (IoT) or an alternative model that uses similar systems and technologies but limi... (WhatIs.com)

  • smart home hub (home automation hub)

    - A smart home hub is a hardware device that connects the devices on a home automation network and controls communications among them. (WhatIs.com)

  • smart sensor

    - A smart sensor is a device that takes input from the physical environment and uses built-in compute resources to perform predefined functions upon detection of specific input and then process data ... (WhatIs.com)


  • Smart grid

    - Terms related to smart grids, including definitions about utility electricity delivery systems and words and phrases about smart meters and distributing, monitoring and billing electrical power.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question About ampere per meter (A/m, Oe, oersted)Powered by ITKnowledgeExchange.com

Get answers from your peers on your most technical challenges

Tech TalkComment



    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.