When an electric current is applied to a loop coil, the effect is equivalent to that of a magnet bar. Therefore, the coil surface has a magnetic field n-s pole generation, that is, there is a magnetic flux across. If the power supply used is alternating current, both the poles of the coil and the magnetic flux across the loop surface will change.

When there is a magnetically conductive metal surface placed above the loop coil, the metal surface will be induced current (i.e., eddy current), eddy current so that the pots and pans of iron atoms in high-speed irregular motion, the atoms collide with each other, the friction and the generation of heat

The greater the current induced the higher the amount of heat generated, the shorter the time required to cook the food. The greater the induced current, the greater the change in magnetic flux across the metal surface, and of course the stronger the magnetic field. As a result, more turns of the coil originally energized by the alternating current need to be wound together.

Because of the high-intensity magnetic field induction, there is no electric current generated on the surface of the stove, so the surface of the stove does not generate high temperatures when cooking food, making it a relatively safe cooking appliance.

The working process of the microwave oven: microwave oven is actually a microwave oscillator, it produces microwaves, wavelength 122 mm, frequency 2450 MHz.

Microwave oscillation in the microwave oven, and make the food contained in the water molecules and it with the same frequency oscillation. This causes the molecules to rub against each other. Friction can generate heat. The higher the frequency of oscillation, the greater the amplitude, the more intense friction between molecules, the more heat generated. Obviously, this way of heating and baking infrared radiation in a different way, it can make the internal and external surface of the food at the same time by the heat, this heating method is very efficient, cook a box of rice, as long as a few minutes, but you can not get the "burnt" effect. To bake bread, kebabs, baked sweet potatoes, only with an electric oven. Some students may have noticed that the microwave oven not only does not have a "burnt", sometimes instead of "burnt". Heating buns a little longer, the core of the buns will become hard and burnt. Why is this? Mainly because the microwave magnetron issued microwave is not uniformly distributed in the microwave oven, but "focus" in a position in the furnace, that is to say, the intensity of the microwave here is the other parts of the hundreds of times. This gathering position is about the upper centimeters in the center of the turntable, a mushroom-shaped position. If you heat a large steamed bun here, you will find that the surface of the bun is not yet hot, and the heart of the bun has already burned dry, forming a mushroom-shaped lining. In order to avoid uneven heating of food, the microwave oven is equipped with a turntable, which automatically keeps rotating when it is switched on, so that the food is heated evenly.

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