Electromagnetic unit conversion (SI system and CGS system conversion)

Friends who come into contact with magnetic materials often encounter a variety of electrical or magnetic units, and since electromagnetics uses Gaussian units in addition to the general international system, this makes us feel that electromagnetics The unit is complicated. For example, the intrinsic coercivity Hcj has different description methods under the two unit systems. 960kA/m under the SI system is 12kOe under the CGS system. Today, I will take you to summarize the units in electromagnetics and the conversion relationship between different unit systems.

What is the unit system?

Various physical quantities are related to each other through equations that describe the laws of nature and equations that define new physical quantities. In order to formulate the unit system and introduce the concept of dimensions, a group of independent physical quantities and their units are usually selected as the basic physical quantities and basic units, and then based on a series of specific physical formulas, the proportional constants are selected to determine other physical quantities (derived Dimension and unit (derived unit) of the quantity). The dimension of the derived quantity is represented by the power of the basic physical quantity, and the derived unit is represented by the basic unit. Some derived units have special names and symbols. As a result, the units of each physical quantity constitute an organic and rule-based whole, which is the physical unit system.

Clever use of different unit systems to express the formula, the highest advantage is that the formula can be greatly simplified, some complex constants can be reduced to 1, which is conducive to our derivation and understanding, which is why there are many in the field of electromagnetics The reason for the unit system.

International system (SI system) and Gauss system (CGS system)

The unit system of electromagnetism in the International System of Units is the MKSA rational system. MKSA stipulates the units of four basic physical quantities in electromagnetism. ), second (s), ampere (A).

The Gauss unit system is established on the basis of the absolute electrostatic unit system (CGSE unit system or esu) and the absolute electromagnetic unit system (CGSM unit system or emu) of electromagnetics. The Gauss unit system is a summary of the above two unit systems. The unified unit system of electromagnetics, so it is also called the mixed unit system. The absolute electrostatic unit system selects three quantities of length, mass, and time as the basic quantities, and the units are centimeters (cm), grams (g), and seconds (s).