The number of household appliances in our kitchens is growing steadily year by year. What 15 years ago was a curiosity is now taken for granted. Today it is impossible to imagine an apartment in which there would be no microwave oven. This is a really convenient device that allows you to not only quickly heat up or defrost, but also to cook food. Moreover, contrary to the fears of many people, the energy consumption during its use is small. This article will discuss microwave oven circuits and other related information.
What is the principle of a microwave oven?
Many do not understand why food is heated in the microwave, and an empty plate remains cold, regardless of the time it was inside. Schemes of microwave ovens and their principle of operation involves increasing only liquids, fats and sugars. This happens due to the fact that the high-frequency radiation generated by the magnetron (it is also called the gun) accelerates only dipole molecules that do not exist outside the humid environment. For this reason, ceramics, glass or plastic do not heat up.
Microwaves themselves cannot penetrate deeply into warmed food, by a maximum of 2-3 cm, but this is quite enough to increase the temperature throughout the entire volume of the product. That is why it seems that the dish is warming up from the inside.
How does a microwave oven work: scheme, operation procedure
If you use special terminology, the information may seem too complicated. Therefore, it makes sense to consider the circuit diagram of a microwave oven with a description of the work in simpler words, as they say "human language".
The basis of the microwave is a high-voltage transformer with two windings - low current (voltage on it rises to 1600 V, and the resistance is about 180 Ohms) and incandescent (not more than 3 V). One of the conclusions of the high-voltage winding is shorted to the device body, and the second goes to the rectifier capacitor, which performs the functions of separation and smoothing. It turns out that it does not allow a possible short circuit to disable the transformer and does not allow ripple.
The filament circuit consists of a winding, combined with a spiral located inside the magnetron. Thanks to their interaction, high-frequency radiation is generated. However, modern microwave ovens are quite moody due to the addition of completely unnecessary components to the electrical circuit of a microwave oven. They, being a weak point, often lead to breakdowns. At the same time, old models work flawlessly for many years.
The most common problem is the lack of contact at the terminal connections, while diagnosing such malfunctions is quite difficult. This happens because without a load all the connections are in working condition, but when the magnetron is started, the problem is detected. An approximate circuit of the microwave oven is located below.
Additional microwave features
Such household appliances can be equipped with a grill and (or) convection. It is worth understanding how these functions are useful and how they are implemented. What is a grill is clear to everyone. But how it is arranged in a microwave oven, few people understand. To implement this function, an ordinary dry heater (steel, brass or copper tube with a spiral inside) or a quartz heater, which is a glass tube filled with sand, is installed in the chamber. It is he who isolates the spiral preventing it from contacting the shell. Both species have certain features. TENY most often you can move them horizontally (from above) to vertical (to the back wall), but the glass tube is easier to clean.
Some electrical circuits for microwave ovens include a fan that delivers hot air from the coil into the chamber. This mode is called convection.
What kind of dishes can I use for a microwave
Many believe that if a microwave oven heats food as if from the inside, then what kind of dishes are used for this is not important. But this is a very dangerous misconception. Metal containers or a spoon in a plate will quickly disable a household appliance. This is what happens.
The microwave oven circuit involves high-frequency radiation, which heats up liquids. If metal comes in its way, the wave is reflected, heading in the opposite direction. The first thing that suffers is the mica plate covering the magnetron gun. This is especially evident if it contains droplets of not washed fat. Then the radiation begins to hit the magnetron, as a result of which it fails.
Do not think that only ironware is dangerous. Plaques with a dusting, foil pattern and even a metallized rim can easily harm the microwave. Therefore, you should carefully consider which cups are in the chamber.
The most common microwave problems
The first thing that most often begins to cause inconvenience is crackling and sparks that appear in the area of the magnetron gun. This starts to burn out the mica plate due to fat adhering to it. Fortunately, if you do not continue to use the faulty device, it is quite simple to fix such a problem. Mica plates are sold in all specialized stores. They can also be purchased online. You should buy a larger sheet and only then, using the old part, as in the template, cut out the necessary shape. If you continue to use the faulty device, the magnetron will not last long.
Another common annoyance is scratches on the inside of the camera. They appear from too large, not in size, plates. If such a problem is found, it is necessary to clean and degrease the cleaved place and paint over with metal enamel. Otherwise, it will turn out the same as heating up metal dishes.
Schemes of microwave ovens of some models contain another weak knot - a glass flask of grill. If fat dries on it, it can cause cracks in it. In order to avoid this situation (if the stains on the handset are already dry), experts recommend turning on the grill mode for a few minutes. Dried fat will burn, after which it will be much easier to clean it.
Microwave Usage Guidelines
It should be understood that some products are not intended for cooking or heating with a similar household appliance. For example, the microwave oven circuit does not allow its use for raw eggs, jacket potatoes, and hard-walled sausages. Such products in the microwave simply explode. Before cooking, eggs should be freed from the shell, and sausages and potatoes should be pierced with a fork.
If the food is not heated in the microwave, but is cooked, it is better to salt it immediately - so the process will go faster. Also in the device you can soften stale bread by putting it in a plastic bag, however, you should be careful. If you overexpose it a little, it will begin to char from the inside, although outwardly this will not be noticeable. When you turn on the function "convection" soften it will not succeed, rather the opposite. It is worth seeing how the fan and the heater are included in the circuit. For general information, a schematic diagram of a microwave oven equipped with the “grill” and “convection” functions is presented below.
Leading manufacturers of microwave ovens represented on Russian shelves
There are a lot of companies offering similar products, and all of them cannot be listed. However, small producers come and go, and the giants, who have won the confidence of the buyer with quality, remain, strengthening their positions more and more. Today, Samsung is the undisputed sales leader not only in Russia but also in the world. Microwaves of this brand are represented by a fairly wide range, and you can meet them in any household appliance store. This brand is appreciated for build quality and reliability. Indeed, in fact, the circuit of the Samsung microwave oven is no different from the device of competitors' devices.
Brands such as Bosch, Candy, Gorenje, Kaiser and LG have also worked pretty well. If you plan to purchase a microwave oven, then it is better to give preference to just one of these manufacturing companies.
What are the indicators of the power network?
Microwave ovens are quite sensitive to voltage drops. If it is lowered, outwardly it will be almost imperceptible, however, the load on all nodes will increase significantly. In this case, the heating rate will be much lower. As for voltage surges, they can easily damage the magnetron or the entire control circuit of the microwave oven.
If in the area where the user lives, such cases are not uncommon, you should take care of acquiring a stabilizing device that will protect not only the microwave, but also other household appliances. In extreme cases, you can do with the installation of a voltage relay. Although it does not equalize the indicators, it will be able to turn off the power in time, not allowing overloads on the magnetron.
Some tips for choosing and purchasing microwave ovens
First you need to decide what functions in the microwave are needed. Indeed, if the owner does not use convection or grill, there is no point in overpaying for them. Choosing a model should not begin in the store, but behind the computer monitor - this will save you from the annoying imposition of a particular microwave by a sales assistant. After all, very often it happens that a person acquires something completely different from what he originally planned.
When 3-4 models are selected, you can advance to the store. The packaging of the purchased goods must not be damaged. Chips, scratches or dents on the microwave case - this is an excuse to refuse to purchase or purchase it at your own risk, but at a much lower cost, since such a product should be classified as discounted.
Carefully study the related technical documentation. We are talking about certificates of conformity and quality. Be sure to clarify the warranty period and make sure that the seller stamps the date of sale, signature and seal of the store. The check must be saved. Otherwise, in case of breakdown, repairs will have to be done at their own expense.
Video tutorial on choosing a household appliance: what you should pay attention to
For those who are already thinking about purchasing a microwave microwave oven, a very informative video is offered, which will describe in detail what you should pay attention to when choosing a similar household appliance. After all, it is always easier and more understandable to perceive information by ear than to get acquainted with it in print.
Final part
Microwave microwave oven is really a great helper in the kitchen. However, for it to last a long time, you should not only choose the right model, but also properly care for the device. It is worth remembering that the microwave does not like dried fat, scratches, surges and voltage drops. And if the device is spared such problems, you don’t have to worry about its performance. So, we can make a logical conclusion that durability is more dependent on the owner and his attitude to household appliances.