What is the principle of microwave oven More details Thank you!

Microwaves are a type of electromagnetic wave. The energy of this electromagnetic wave is not only much greater than the usual radio waves, but it is also very large"Personality", the microwave is reflected as soon as it touches the metal, and the metal has no way to absorb or conduct it; Microwaves can pass through insulating materials such as glass, ceramics, plastics, etc., but do not consume energy; In the case of food containing water, not only can it not be transmitted by microwaves, but its energy will be absorbed.

Microwave ovens are made using these properties of microwaves. The shell of the microwave oven is made of metal materials such as stainless steel, which can block the microwave from escaping from the furnace so as not to affect people's health. Food containers are made of insulating material.

The heart of a microwave oven is the magnetron. This tube, called a magnetron, is a microwave generator that produces microwaves that vibrate at a frequency of 100 million vibrations per second. This kind of microwave, which is invisible to the naked eye, can penetrate the food up to 5cm deep, and make the water molecules in the food also move with it, and the vigorous movement produces a large amount of heat energy, so the food"Cook"Cooked.

This is how microwave heating works. When cooking food on a regular stovetop, the heat always gradually enters the inside of the food from the outside of the food. In the microwave, the heat goes directly into the food, so the cooking speed is 4 to 10 times faster than other stoves, and the heat efficiency is as high as 80%.

At present, the thermal efficiency of other stoves cannot be compared.

Microwave ovens, on the other hand, maintain the vitamins and natural flavors of food well due to the short cooking time. For example, boiling green peas in the microwave can make almost no loss of vitamin C at all. In addition, microwaves can also disinfect and sterilize.

When using the microwave, care should be taken not to leave it empty"Burn", because empty"Burn", the energy of the microwave cannot be absorbed, so it is easy to damage the magnetron. In addition, human tissues contain a lot of water, so be sure to open the furnace door after the magnetron stops working and extract food.

This is how microwaves work. Therefore, heated food does not cause damage to the human body caused by microwaves.

Molecules have a specific vibration frequency, and the microwave generated by the magnetron is just the vibration frequency of the water molecule, which produces resonance, and the water molecule will move violently and the temperature rises.

The microwave oven principle is an electromagnetic wave with a frequency of 300MHz 300GHz, which has a very short wavelength and has the properties of visible light, propagating in a straight line.

Microwaves can be reflected when encountering metal materials, can penetrate insulating materials such as glass, plastics, ceramics, etc., and can be absorbed when encountering proteins, fats and other media containing water, and turn the electromagnetic energy of microwaves into heat energy. Due to the high frequency of microwaves, their transmission requires the use of high conductivity waveguides.

Although the frequency band of microwave is very wide, the frequency band that is actually used for microwave heating is very narrow, and the main reason is to avoid using more frequencies and prevent interference to microwave communication. Internationally, household microwave ovens have two frequencies of 915MHz and 2450MHz, 2450MHz is used for home cooking utensils, and 915MHz is used for drying and disinfection.

Details:

The heated medium can generally be divided into non-polar molecular dielectric and polar molecular dielectric. Polar molecules do not show polarity in the absence of an applied electric field. If this medium is placed in an applied electric field, each polar molecule forms an orderly arrangement in the direction of the electric field force and induces opposite charges on the surface of the dielectric, a process known as polarization.

The stronger the applied electric field, the stronger the polarization. When the applied electric field changes direction, the polar molecules also form an orderly arrangement in the opposite direction.

If an alternating electric field and a magnetic field are applied, the polar molecules will be magnetized repeatedly, and the higher the frequency of the alternating electric field, the faster the polarization of the polar molecules. At this time, the kinetic energy of the thermal motion of the molecule increases, that is, the heat increases, and the temperature of the food also increases, which completes the conversion of electromagnetic energy to heat energy.