Magnetron: principle of operation and device

To obtain particular and high oscillations, use magnetrons. Electric and magnetic fields operate with high force. As a result, high frequency oscillations occur. A frequently used version of the device is a multi-cavity one. In such a magnetron, the electrons are acted upon by just three fields:

• Electric;
• Magnetic;
• Microwave.

Magnetron: what it is and how it appeared

For the first time this term was used in 1921 by the American physicist A. Hall. His research and experiments were continued further, which led to the appearance of many varieties of magnetrons, which were used in radio electronics. The patent for this invention was given to A. Jacquet in 1924. It was he who invented the modern magnetron, whose operation principle is based on the interaction of two fields.

In the following decade, the development of magnetrons for the generation of microwave waves was carried out. The main task was to increase the frequency of oscillations, which only the Soviet scientists managed to do. They increased the original value by two times, using copper as the anode material.

Device

The heart of the magnetron is the anode block, consisting of a copper cylinder, with a hollow inside. In its center there are cavities, they are a ring system of three-dimensional resonators. In the middle of the anode there is a hole, it is through it that the power is connected. Also, the anode is connected to the cathode from it. It is a filament, it is heated and runs through the entire middle of the anode. To ensure the output of high-frequency oscillations, this output is set in one of the resonators. Inside the anode block is a vacuum. For its cooling, ribbed radiators are installed on the surface.

Place this block so that it is between the magnets, creating a magnetic field of sufficient strength. The voltage between the anode and the cathode is set, so that the positively charged pole is at the anode. Electrons from the cathode begin to move because of the action of the electric field. They must move to the anode, and the magnetron, whose principle of operation is in a magnetic field, returns it figuratively to the cathode.

To achieve the effect, when electrons move along the circumscribed circle and are near the anode, but come back, it is possible, if certain conditions are met in two related fields. In this state, only a small fraction of all the electrons leaving the cathode remain on the anode.

Returning to the cathode, some of the electrons are replaced. This process continues, forming a charge near the anode in the form of a ring. Such a charge begins to form near each resonator, undamped high-frequency oscillations appear. Output such fluctuations can be turns of wires, placing them in any of the resonators. These oscillations are then transmitted to the waveguide (or coaxial line).

Magnetron can be called a microwave instrument, it is a generator, vacuum, the motion of electrons in it occurs in two fields: electronic and magnetic. The magnetron creates the principle of the action of these two fields, which form the third - microwave.

Application

They can be used in radio engineering. For example, when composing radar maps. For this purpose, the magnetron should consist not only of a horn irradiator, but also of a parabolic reflector. With the help of high-intensity pulse control, a short pulse of microwave radiation is created. Part of the energy, reflected, returns back to the waveguide and antenna, which directs it to the receiver. After processing, the data appears on the radar map.

Application in everyday life

In ovens, whose operation is based on microwaves, the principle of operation is slightly different. The magnetron for a microwave oven has a transparent hole at the end of the waveguide for radio frequencies that are formed in the cooking compartment. Therefore, it is important to include such an oven only with the presence of food in it. Without this condition, standing waves will cause arcing, since the magnetic waves are not absorbed, but were returned back. If it lasts a long time, the magnetron will just break down. The speed at which food is cooked in a microwave oven depends directly on the power of the magnetron.

Most microwave ovens have a power of 700 to 850 watts. This is quite enough to boil a glass of water in just 2-3 minutes. Magnetron for microwave "Saturn", depending on the model, can have different power. The choice of microwave technology of this company can begin with the comparison of magnetrons, and then additional functions.

Microwave purchase

When buying a microwave oven, you should know the principle of its operation. Many are wary of this technique, mistakenly believing that this is a source of radiation. In fact, it operates the principle of microwave, which follows from the name itself. Microwave - is nothing like "ultrahigh frequencies." Radiation, of course, it does not radiate, but it is necessary to handle this technique carefully.

The microwave itself already has protection from the environment from microwave radiation. Such a furnace is equipped with a special sensor that will shut off the magnetron if the door is open. Shut down the magnetron, the principle of which is to produce microwave waves, can not, if the rules of operation are violated. If you put in a furnace, for example, a metal bowl, it will simply disable the entire device.

Waves from the microwave oven can go out no more than five meters. Therefore, at a time when it works, it is better to stay away. However, the layout of the kitchens of most apartments do not allow this, because you have to go to another room.

The electromagnetic field, without contact, heats the food placed in the microwave oven. Moreover, the heating process takes place directly within the product, which shortens the cooking time to several minutes. Do not preheat the dishes in which the food is located.

For the best result of cooking you need to know the culinary tricks of cooking certain products. Taking into account the fact that time goes on, and the device of microwave ovens does not change, we can assume their further and constant fastening for kitchens of many consumers.

Purchase of magnetron for microwave

Buying yourself a magnetron, you need to know the marking. In order not to make the mistake of buying a magnetron on the microwave LG, you need to know what they are. The weakest power of the magnetron is 2M213. Its output power under load and typical are equal to 700 and 600 W respectively, the anode value is 3.95 kVp, and the frequency is 2460 MHz.

Magnetrons with mean values of several. The main one is 2M214. In this model, the frequency is the same, the anode value is slightly higher - 4.20 kVp. Output power under load and typical - 1000 and 850 W respectively.

The maximum values of the indicators for the magnetron mark2M246. At the same frequency, the anode value is greater - 4.40 kVp, the average output power at the load is 1150 W, typical - 1000 W.

Is it possible to replace yourself?

Any of the types of magnetron for microwave LG can be replaced with a similar one for another firm, for example, "Samsung". Similarly, you can replace the magnetron for a Samsung microwave with a suitable power element from another company. If the model of household microwave oven was released a long time ago, it is very difficult to find the part of the corresponding brand. Perhaps the manufacturer has already withdrawn from production this species.

But even if you know the principle of the magnetron's operation, you should not fix this technique yourself at home yourself.

You can buy a magnetron for the microwave oven 2M218 JF Daewoo by ordering in specialized stores or directly from the manufacturer. It costs about 2 thousand rubles.

The basis of microwave operation

The heating of products in a microwave oven is as follows: any food contains molecules of water, it, in turn, consists of charged positively and negatively particles. Such molecules act as a dipole, because they conduct well the waves of electricity.

Conclusion

Frequent breakdown of microwave ovens - the failure of the magnetron. Buy a magnetron on the microwave LG (as, indeed, other manufacturers of these appliances) and replace it yourself will be quite problematic. Even if there is an appropriate element, only the master can install it.

Before buying a device, you should compare its price with the cost of the microwave itself. It often happens that repairs cost more than buying. Always consider this factor.

So, we found out why an element such as a magnetron is needed, and in what areas it is applied.