To obtain particular and high vibrations, magnetrons are used. Electric and magnetic fields act with high force. As a result, high frequency oscillations occur. A frequently used type of device is multi-cavity. In such a magnetron, three fields act on electrons at once:
- electric;
- magnetic;
- Microwave
Magnetron: what it is and how it appeared
This term was first 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 began to be used in radio electronics.
A patent for this invention was obtained by A. Jacquet in 1924. It was he who invented the modern magnetron, the principle of which is based on the interaction of two fields.
In the next decade, the development of magnetrons for the generation of microwave waves was carried out. The main task was to increase the oscillation frequency, which only Soviet scientists managed to do. They doubled the initial value by using copper as the material of the anode.
Device
The magnetron's heart is an anode block, consisting of a copper cylinder, with a void inside. There are cavities in its center; they are a ring system of volume resonators. There is a hole in the middle of the anode, it is through it that the power is connected.
Also from it the anode is connected to the cathode. It is a filament, it is heated and passes through the entire middle of the anode. To ensure the output of high-frequency oscillations, such an output is installed in one of the resonators. Inside the anode block is a vacuum. To cool it, finned radiators are installed on the surface.
This block is placed so that it is between magnets that create a magnetic field of sufficient strength.
Set the voltage between the
anode and cathode, and so that a positively charged pole is located at the anode. Electrons from the cathode begin to move due to the action of the field of electricity. They should move to the anode, and the magnetron, the principle of which is a
magnetic field, returns it figuratively to the cathode.
It is possible to achieve the effect when the electrons move along the described circle and at the same time are near the anode, but come back, if certain conditions are met in two connected fields. In this state, only a small fraction of all the electrons emitted from the cathode remain on the anode.
Returning to the cathode, part of the electrons is replaced. This process continues, forming a ring-shaped charge near the anode. Such a charge begins to form near each resonator; undamped high-frequency oscillations appear. Such oscillations can be derived by turns of wires, placing them in any of the resonators. Following these oscillations are transmitted to the waveguide (or coaxial line).
A magnetron can be called a microwave device, it is a generator, a vacuum, the movement of electrons in it occurs in two fields: electronic and magnetic. The magnetron creates the principle of action of these two fields, which form the third - microwave.
Application
They can be used in radio engineering. For example, when compiling radar maps. For this, the magnetron should consist not only of a horn irradiator, but also of a parabolic reflector. By controlling high-intensity pulses, a short microwave radiation pulse is created. Part of the energy, reflected, returns back to the waveguide and antenna, which direct it to the receiver.
After processing, the data appears on the radar map.
Domestic use
In ovens whose operation is based on microwaves, the principle of operation is slightly different. A microwave magnetron has a transparent hole at the end of the waveguide for the radio frequencies that form 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 sparking, since the magnetic waves were not absorbed, but were returned. If this lasts a long time, the magnetron will simply break. The speed at which food is cooked in the microwave depends directly on the power of the magnetron.
Most microwave ovens have power from 700 to 850 watts. This is enough to boil a glass of water in just 2-3 minutes. Magnetron for microwave Saturn, depending on the model, may have different power. The choice of the microwave of this company can begin with a comparison of magnetrons, and then additional functions.
Microwave purchase
When buying a microwave oven, you should know the principle of its action. Many are wary of this technique, mistakenly believing that it is a source of radiation. In fact, the microwave principle applies in it, which follows from the name itself. Microwave - nothing more than "ultra-high frequencies." She, of course, does not radiate radiation, but it is necessary to handle such equipment carefully.
The microwave itself already initially has the protection of others from microwave radiation. Such a furnace is equipped with a special sensor that will turn off the magnetron if the door is open. A magnetron, the principle of which is to generate microwave waves, will not be able to complete work if the operating rules are violated. If you put in a furnace, for example, a metal bowl, it will simply disable the entire device.
The waves from the microwave oven can go out no further than five meters.
Therefore, at the time when it works, it is better to stay away. However, the layout of the kitchens of most apartments does not allow this, because you have to go into another room.
An electromagnetic field non-contact heats food placed in the microwave. Moreover, the heating process takes place directly within the product, which reduces cooking time to several minutes. No need to pre-heat the dishes in which the food is located.
For the best cooking result, you need to know the culinary tricks of the preparation of certain products. Given the fact that time is running out, and the arrangement of microwave ovens does not change, we can assume their further and permanent assignment to the kitchens of many consumers.
Purchase of a magnetron to microwave
Buying a magnetron yourself, you must know the marking. In order not to make a mistake when buying an LG magnetron , you need to familiarize yourself with what they are. The weakest power of the magnetron is 2M213. It has an output power at load and typical power of 700 and 600 W, respectively, the anode value is 3.95 kVp, and the frequency is 2460 MHz.
There are several magnetrons with average values. The main one: 2M214. This model has the same frequency, the anode value is slightly higher - 4.20 kVp. The output power at load and typical is 1000 and 850 W, respectively.
The maximum values of the indicators of the magnetron brand 2M246.
At the same frequency, the anode value is greater - 4.40 kVp, the average output power at load - 1150 W, typical - 1000 W.
Is it possible to do it yourself
Any type of magnetron for LG microwave ovens can be replaced by a similar one for another company, for example, Samsung. Similarly, you can replace the magnetron for the Samsung microwave with a suitable power element from another company. If a model of a household microwave oven has been released for a very long time, then it is very difficult to find a part of the corresponding brand. Perhaps the manufacturer has already discontinued this species.
But even if you know the principle of operation of a magnetron, you should not do it yourself at home.
You can buy a magnetron for a 2M218 JF Daewoo microwave oven yourself by ordering in specialized stores or directly from the manufacturer. It costs about 2 thousand rubles.
The basis of the microwave
The heating of products in the microwave occurs as follows: any food contains water molecules, it, in turn, consists of positively and negatively charged particles. Such molecules act as a dipole, because they conduct electricity waves well.
Conclusion
Frequent failure of microwave ovens is the failure of the magnetron. Buy a magnetron on a microwave LG (as, incidentally, other manufacturers of these household appliances) and replace it yourself will be quite problematic. Even if there is a suitable 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 will cost more than the purchase. Always consider this factor.
So, we found out why such an element as a magnetron is needed, and in what areas it is used.