Structure and principles of microwave operation

Microwave ovens are becoming more and more familiar in families, it is very versatile, is a kitchen that saves time thanks to microwave radiation that burns food for human consumption. Every day you have been exposed to using it often but have you ever thought about why it could do it?

The following article will briefly introduce the operating principle as well as the structure of the microwave for users to better understand the device they are using.

Microwave structure consists of main parts:

1. Usable space.
2. Microcontroller circuit (microcontronller),
3. Magnetron - source of broadcasting.
4. Waveguide (Waveguide).

Metal mesh is often observed at the microwave door.

The cooking compartment is a Faraday cage consisting of metal or metal mesh surrounded, ensuring waves do not leak out. Metal mesh is often observed at the microwave door. The holes in this grid are much smaller than the wavelength (12cm), so the microwaves do not leak out, but he is bright (at a much higher wavelength) still passing through, helping to close the food inside. Microwave uses microwave waves to heat food.

Microwaves are generated from an electromagnetic oscillator and amplified by Magnetron acting as a 3-pole electronic lamp. Energy (microwaves) from a transmitter (magnetron) is transmitted along a waveguide to a dispersed fan (above the top of the furnace) to bring waves to all sides (Figure 1-21). In the middle of the kiln the waves disperse steadily through the reflection of the waves onto the walls of the furnace. Food is heated by water molecules.

The heating is divided into two stages:

1. The water contained in the food is heated by ultra-short waves.
2. Hot water will transfer heat to other parts of the food.

Magnetron broadcasting department

The magnetron consists of a hollow metal cylinder, the anode is anode (anode), the inner cavity resonance is placed on the inside. To increase the frequency from 50 Hz to 2450 Hz, an oscillator is used where the essential part is a parallel resonance circuit . Each cavity is equivalent to a parallel resonance circuit.

In the middle of the hollow cylinder is the cathode, which has a filament.

Inside the magnetron is a vacuum, between negative and positive electrodes, a voltage of about 2300 volts is used to create a magnetic field. This magnetic field moves electrons from the cathode to the anode. In order to create and keep vibrations at high frequencies, the electromagnetic must move in a spiral way before the resonant cavities. This path is obtained by a magnetic field created by a magnet bar whose line of gravity is perpendicular to the electric field E.

In a strong electromagnetic field, the water molecule is oriented in the direction of the field lines. Under the effect of electromagnetism, hydrogen and oxygen atoms change extreme 2.45 billion times in a second. The friction between water molecules together produces heat. The water in the food is heated quickly and gives energy to other ingredients of the food, so the whole food is heated.