电加热器是指利用电能达到加热效果的电器，按加热方式的种类来区分，大致可分为三类:

  1、电磁加热-电磁加热是通过电子线路板组成部分产生交变磁场、当用含铁质容器放置上面时，容器表面具切割交变磁力线而在容器底部金属部分产生交变的电流(即旋涡)，涡流使容器底部的铁原子高速无规则运动，原子互相碰撞、摩擦产生热能，从而起到加热物品的效果。因为是铁制容器自身发热，所以热转化率特别高，最高可达到95%.电磁炉、电磁灶都是采用的电磁加热技术。

  2、红外线加热--红外线的传热形式是辐射传热，由电磁波传递能量。在远红外线照射到被加热的物体时，一部分射线被反射回来，一部分被穿透过去。当发射的远红外线波长和被加热物体的吸收波长一致时，被加热的物体吸收远红外线，这是物体内部分子和原子发生共振--产生强烈的振动、旋转，而共振和旋转使物体温度深高，达到了加热的目的。

  3、电阻加热--利用电流通过电热体放出热量来加热坯料的加热方法。常见的电阻丝加热，陶瓷加热器以及电阻圈加热，石英管加热，原理上都属于电阻式加热。

  三种加热方式的对比:

  1、电阻式加热器的加热是最原始的，所以热效率也是最差的，通常热效率只有百分之七十左右，大量的热能散发到空气中。

  2、红外线的加热方式相比电阻要好一点，但是依然大量的热量散发到空气中，只不过红外线本身散发到空气中的，而是被加热的物体把热量散发到空气中。

  3、电磁加热器工作时是有一层保温层把受热物体包裹住的，然后磁场透过保温层直接加热物体本身，所以热效率是最高的几乎热能没有流失，其效率超过95%以上，而且电磁加热器是被加热物体自身发热所以也没有热传递的损失，整体节能是同等条件下电阻加热30%-70%，红外线加热器因为其加热特点无法和电磁加热做详细比较，但散发出的温度上来计算，同等条件下应该电磁加热比红外线加热节省能源在20%以上

  Electric heaters refer to electrical appliances that use electric energy to achieve heating effects. They can be roughly divided into three categories according to the types of heating methods:
  1. Electromagnetic heating - electromagnetic heating generates an alternating magnetic field through electronic circuit board components. When an iron containing container is placed on it, the surface of the container cuts the alternating magnetic line of force and generates an alternating current (i.e. vortex) at the metal part at the bottom of the container. The vortex 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, thus heating articles. Because the iron container heats itself, the heat conversion rate is particularly high, up to 95%. The induction cooker and the induction cooker all use electromagnetic heating technology.
  2. Infrared heating -- The heat transfer form of infrared is radiation heat transfer, which transfers energy by electromagnetic waves. 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. This is because the molecules and atoms inside the object resonate - generating strong vibration and rotation, which makes the object temperature deep and high, thus achieving the purpose of heating.
  3. Resistance heating -- A heating method that uses the current to release heat through the electric heater to heat the blank. Common resistance wire heating, ceramic heater and resistance coil heating, and quartz tube heating are all resistance heating in principle.
Comparison of three heating methods:
  1. The heating of resistance heater is the most primitive, so the thermal efficiency is also the worst. Generally, the thermal efficiency is only about 70%, and a large amount of heat energy is emitted into the air.
  2. The infrared heating method is better than the resistance, but still a lot of heat is emitted into the air. Only the infrared itself is emitted into the air, but the heated object emits heat into the air.
  3. When the electromagnetic heater works, it has a thermal insulation layer to wrap the heated object, and then the magnetic field directly heats the object itself through the thermal insulation layer, so the thermal efficiency is the highest, almost no heat loss, and its efficiency exceeds 95%. Moreover, the electromagnetic heater is heated by the heated object itself, so there is no heat transfer loss. The overall energy saving is 30% - 70% of resistance heating under the same conditions, The infrared heater cannot be compared with electromagnetic heating in detail due to its heating characteristics, but the temperature emitted can be calculated. Under the same conditions, electromagnetic heating should save more than 20% energy than infrared heating