Electromagnetic Field Generation and How to Choose an Electromagnetic Field Generator
Electromagnetic field is a general term for the unity of electric and magnetic fields that are intrinsically linked and interdependent. The time-varying electric field produces a magnetic field, and the time-varying magnetic field produces an electric field. Electromagnetic fields can be caused by charged particles moving at a variable speed, or by currents with varying strengths. Regardless of the cause, the electromagnetic field always propagates around at the speed of light, forming electromagnetic waves. The electromagnetic field is the medium of electromagnetic action, has energy and momentum, and is a form of existence of matter. The properties, characteristics and the law of motion change of the electromagnetic field are determined by Maxwell's equations. Time-varying electromagnetic field. Time-varying electromagnetic fields are significantly different from static electric and magnetic fields, and there are some effects due to time-varying. These effects have important applications and drive the development of electrotechnical technology.
At present, the commonly used types of magnetic field generators generally include fixed magnetic field, Helmholtz coil, helical coil, and electromagnet and other magnetic field generators.
Fixed magnetic field, the standard magnetic field is composed of multiple permanent magnets, through the magnetic field loop, to achieve a constant magnetic field in the gap, the magnetic field size is generally 100 gauss and 1000 gauss, which can be used for Gauss meter calibration, etc.
The Helmholtz coil is composed of two flat coaxial single coils. A spherical uniform magnetic field is generated between the two coils. The size of the uniform magnetic field is changed by changing the current size. It has adjustable magnetic field, high uniformity, high sensitivity, The uniform area is large and the magnetic field is generally below 1000GS. According to the direction of the magnetic field and the size of the magnetic field, one-dimensional Helmholtz coils, one-dimensional compensation Helmholtz coils, and three-dimensional Helmholtz coils can be designed to generate DC magnetic fields. AC magnetic field.
The magnetic field of the solenoid coil is composed of a single helical coil, which generates a long cylindrical uniform magnetic field in the coil. The size of the magnetic field in the uniform area is changed by changing the current size, but the uniformity is slightly worse than that of the Helmholtz coil.
The electromagnet is composed of two flat coaxial single coils. The magnetic field in each coil is derived from pure iron. A uniform magnetic field is generated in the gap between the two pure irons. The magnetic field can be changed by changing the current size. Strong magnetic field and other characteristics, the highest magnetic field is up to 10T.
To sum up, we choose the appropriate type of magnetic field generation according to the type of magnetic field, the size of the magnetic field, the size of the uniform area, and the uniformity.
