The principle of operation of the microwave

The first to discover the possibility of microwave radiation to heat products was US engineer Percy Spencer. It is he and patented microwave.

Judging from eyewitness accounts, the idea of ​​its creation came to his mind when he stood for several hours near the magnetron and found a piece of chocolate melted in his pocket.

The device is able to heat food without heat energy and this is more like a radio transmitter than a familiar stove. The main active element is Microwave microwaves are a form of electromagnetic energy, like light and radio waves.

At the speed of light they propagate towards the subject in the form of microwave waves, the length of which ranges from 0.01 to 1 m.

REFERENCE! Microwaves are also used in civilian radar, radio navigation, satellite television, mobile communications, etc. Microwaves in the environment radiated by the sun and are measured by certain instruments.

How is the microwave arranged? Oven with control panel, waveguide, rotating stand, transformer, capacitor and magnetron - these are the basic elements of building a microwave oven.

The microwave operation scheme is as follows: from the control panel, electric current enters the transformer, then to the capacitor, where power is increased and transmitted to the magnetron.

IMPORTANT! High voltage applied to the filament (of the order of 3-4 kW) so that its antenna can emit quite strong microwave waves.

Interacting with water molecules in food an electromagnetic field with a frequency of 2450 MHz is converted by a waveguide contained in any microwave.

Thermal fuses or thermal relays serve for the safety of the device and do not allow its overheating.

The principle of operation of the fuse is very simple. In the place where it is necessary to control the temperature, its aluminum body is attached using a special connection from the flange. This ensures maximum thermal contact. The metal plate inside the thermal relay is fundamentally tuned to a specific temperature.

Microwaves also equipped with fans, which suck in air from the outside, and then through the blower with a ventilation system distribute it inside the housing. The fan motor is a conventional single-phase AC induction motor.

IMPORTANT! A system of three microswitches is provided to avoid turning on the open microwave.. One of them turns off the magnetron. The next includes a backlight. And the third is designed to notify the control unit of the opening of the door.

To the main functions of the control unit can include:

  • device power regulation;
  • automatic shutdown after the programmed period.

Since the microwaves produced by the furnace act specifically on water molecules. In other words, all that is needed is the content of a small amount of water in the food located in the chamber.

Food temperature increase in an oven under the influence of microwaves it resembles a process when hands get warmed up if we rub them very hard. The similarity also lies in the fact that when one palm rubs against the surface of the other, heat seeps into soft tissues. Microwaves work on the same principle, namely on a small surface (1-3 cm), without penetrating deep into the subject.

The emitted microwaves come in contact with water molecules, causing them to move faster and warmer foods. There are millions of molecules in a drop of water, and when a microbeam enters them, it penetrates into food to a depth of 2.5 cm, causing them to sway under the influence of an electromagnetic field. During this friction, heat is released.

In this way, Foods with a high liquid content heat up faster.

IMPORTANT! Scientists still argue how harmful the microwave is and how it affects the quality of products. but World Health Organization States that Microwave ovens do no harm to humans, nor on food consumed.

Almost all modern furnaces have grill mode. When not only the camera is heated inside, but also the heat is supplied using a special awning - a curved metal device located at the top of the camera. They are called heaters - from the "heat electric heater."

In modern ovens, in addition to the grill mode, there is convection mode. When the chamber is effectively blown from the heating element to the grill. The system is a circulator. Convective heat transfer, as applied to a furnace, is heat transfer using air molecules. Using a fan is usually called convection mode.

Modern models have a number of recipes and cooking methods built into the computer.

Watch the video: How a Microwave Oven Works (December 2019).


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