Electric heaters refer to electrical appliances that use electric energy to achieve heating effects. They can be divided into three categories according to the types of heating methods:
1. Electromagnetic heating
Electromagnetic heating generates an alternating magnetic field through the components of electronic circuit board. When a ferrous container is placed on it, the surface of the container will cut the alternating magnetic line of force and generate an alternating current (eddy current) at the metal part at the bottom of the container. The eddy current makes the iron atoms at the bottom of the container move irregularly at high speed, and the atoms collide and rub with each other to generate heat energy. So as to heat the articles [1]. Because the iron container is self heating, all heat conversion rates are particularly high, up to 95%. Induction cooker and induction cooker are all electromagnetic heating technologies.
2. Infrared heating
The heat transfer form of infrared ray is radiation heat transfer, which transfers energy by electromagnetic wave. When the far infrared ray shines on the heated object, part of the ray is reflected back and part is penetrated. When the wavelength of the far infrared ray emitted is consistent with the absorption wavelength of the heated object, the heated object absorbs the far infrared ray. At this time, the molecules and atoms inside the object have a "resonance" - generating strong vibration and rotation, which increases the temperature of the object and achieves the purpose of heating [2].
3. Resistance heating
The heating method of heating the blank by using the electric current to release heat through the electric heating body. Common resistance wire heating, ceramic heater, resistance coil heating and quartz tube heating are all resistance heating in principle.
