Microwave Oven Magnetron

The core of the voltage system in the microwave that generates microwave energy from electric current is called the microwave oven magnetron. It is the electron tube that produces the requisite 2450 MHz of microwave energy that cooks food.

The operation of microwave oven magnetron is based on the theory that energy produced by the motion of electrons under the combined effect of magnetic and electric fields can be used to cook food. The electrons should flow from the cathode end to the anode end for the tube to be operational. It produces RF energy, and this energy is radiated into the cooking cavity where it is absorbed by the food.

The tube makes use of half wave voltage double circuit and permanent magnets to oscillate and convert voltage supply into 2450 MHz cooking frequency microwave energy. A microwave usually requires 1100 W electric energy to create microwave energy of 700 W.

Microwave heating is efficient on liquids like water, especially frozen water, rather than on sugars and fats. It is a misconception that a microwave oven cooks food from the inside. On the contrary, microwaves are absorbed by the outer layers of food. Microwave ovens induce deeper initial heat than other methods because the microwaves penetrate non-conductive dry substances at the surface of common foods. The depth of penetration of microwaves depends on food composition and frequency of microwaves - lower microwave frequencies penetrate better.

Though there is no change in the intensity of radiation while cooking, the magnetron, driven by a linear transformer, is turned off and on in cycles of several seconds at a time.

It is important that food should be present in the microwave oven when it is being operated so that the microwaves can be absorbed. If there is no food, the waves will be reflected into the wave field and cause arcing due to their intensity. If arcing continues for long periods, the magnetron itself may be damaged.

Modern microwaves come with a center plate that rotates to ensure that food is evenly heated from all sides. This plate has the capacity to absorb microwaves which makes it possible for smaller quantities to get heated and prevent arcing causing resonant reflections.

Exposure to microwave radiation involves some risks to the human body. The eye lens has no cooling blood flow, which in turn makes it more liable to get damaged due to overheating on exposure to microwave radiation. A microwave with a poor sealing or a warped door could prove dangerous.

Since microwaves require a considerably high voltage power supply, they can be electric hazards.

A magnetron may contain berrylia, which is a confirmed human carcinogen. Broken magnetrons should never be handled directly. It has long been suspected that the microwave oven magnetron is a possible source of cancer.

Autor: Alen Cauller

Microwave oven is a kitchen appliance that serves as a healthy and fast mode of cooking. Small microwave ovens are also available for reheating and minor cooking purposes. And, to know more about them, you may visit the specified link.

Added: January 1, 2010
Source: http://ezinearticles.com/