The number of household appliances in our kitchens is steadily growing year by year. What was a curiosity 15 years ago 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 not only to quickly reheat or defrost, but also to cook food. In addition, contrary to the fears of many people, the consumption of electricity during its use is small. This article will cover microwave oven circuits and other related information.
How does a microwave oven work
Many do not understand why food is heated in the microwave, but an empty plate remains cold, regardless of the time it was inside. Schemes of microwave ovens and their principle of operation involves the increase of only liquids, fats and sugars. This happens due tothe fact that high-frequency radiation produced by a magnetron (also called a gun) accelerates only dipole molecules, which are not found outside a humid environment. It is for this reason that ceramics, glass or plastics do not heat up.
Microwaves themselves cannot penetrate deeply into the heated food, by a maximum of 2-3 cm, but this is quite enough to raise the temperature throughout the entire volume of the product. That is why it seems that the dish is warming up from the inside.
How a microwave oven works: diagram, operation
If you use technical terminology, the information may seem too complicated. Therefore, it makes sense to consider a schematic diagram of a microwave oven with a description of the work in simpler words, as they say "human language".
The microwave oven is based on a high-voltage transformer with two windings - low-current (the voltage on it rises to 1600 V, and the resistance is about 180 Ohms) and incandescent (no more than 3 V). One of the leads of the high-voltage winding is shorted to the body of the device, 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. Due to their interaction, high-frequency radiation is produced. However, modern microwave ovens are rather capricious due to the addition of a microwave to the electrical circuit.furnaces of completely unnecessary nodes. It is they who, 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 on the terminal connections, while diagnosing such malfunctions is quite difficult. This is because, without load, all connections are in working order, but when the magnetron is started, the problem is detected. An approximate diagram of the microwave oven is located below.
Additional functions of microwave ovens
Such household appliances may be equipped with a grill and/or convection. It is worth understanding what these functions are useful for and how they are implemented. Everyone understands what a grill is. But how it works in a microwave oven, few people understand. To implement this function, a conventional dry heating element (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 coming into contact with the shell. Both types have certain features. Heating elements can most often be moved from a horizontal position (from above) to a vertical position (towards the back wall), but the glass tube is easier to clean.
Some microwave oven circuitry includes a fan that blows hot air from the coil into the chamber. This mode is called convection.
Which dishes can be used for 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 delusion. Metal containers or a spoon in a plate will quickly disable a household appliance. Here's what happens.
The scheme of the microwave oven implies high-frequency radiation, which heats up liquids. If metal comes across in its path, the wave is reflected, heading in the opposite direction. The first thing that suffers is the mica plate covering the magnetron gun. This begins to manifest itself especially clearly if there are droplets of unwashed fat on it. Further, the radiation begins to hit the magnetron, causing it to fail.
Don't think that only iron utensils are dangerous. Plates with a coating, a foil pattern, and even a metallized rim can easily harm the microwave. Therefore, you should be careful about which cups are in the chamber.
Most Common Microwave Oven Problems
The first thing that most often causes inconvenience is the crackling and sparks that appear in the area of the magnetron gun. This begins to burn out the mica plate due to the fat adhering to it. Fortunately, if you do not continue to use the faulty device, fixing such a problem is quite simple. Mica plates are sold in all specialized stores. They can also be purchased online. You should buy a sheet of a larger size and only thenold part, as per the pattern, cut out the required shape. If you continue to use the faulty device, the magnetron will not last long.
Another common nuisance 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 chipped area and paint over with enamel on metal. Otherwise, it will be the same as heating a metal dish.
Schemes of microwave ovens of some models contain another weak node - a glass grill flask. If grease dries on it, it can cause cracks to appear in it. In order to avoid such a situation (if the stains on the tube have already dried up), experts recommend turning on the “grill” mode for a few minutes. Dried grease will burn off, making it much easier to clean off.
Microwave Rules
Please understand that some foods are not intended to be cooked or reheated with this appliance. For example, the scheme of the microwave oven does not allow its use for raw eggs, jacket potatoes, sausages in a hard shell. Such products simply explode in the microwave. Eggs before cooking should be freed from the shell, and sausages and potatoes should be pierced with a fork.
If food is not warmed up in the microwave, but cooked, it is better to s alt it right away - so the process will go faster. You can also soften stale bread in the device by puttingit in a plastic bag, but you should be careful when doing this. If it is overexposed a little, it will begin to char from the inside, although this will not be noticeable externally. When the “convection” function is turned on, it will not be possible to soften it, rather the opposite. It is worth seeing how the fan and heating element are included in the circuit. For general information, below is a schematic diagram of a microwave oven equipped with "grill" and "convection" functions.
Leading microwave oven manufacturers presented on Russian shelves
There are a lot of firms offering similar products, and it is impossible to list them all. However, small producers come and go, but the giants, who have won the trust of the buyer with their quality, remain, strengthening their positions more and more. To date, the undisputed sales leader not only in Russia, but also in the world, is the Samsung concern. Microwaves of this brand are represented by a fairly wide range of models, and you can find them in any home appliance store. This brand is valued for build quality and reliability. After all, in fact, the scheme of the Samsung microwave oven is no different from the device devices of competitors.
Brands such as Bosch, Candy, Gorenje, Kaiser and LG have also proven themselves well. If you plan to purchase a microwave oven, then it is better to give preference to one of these manufacturers.
What is affected by the performance of the power grid
Microwave ovens are quite sensitive to voltage fluctuations. If it is lowered, outwardly it will be almost imperceptible, however, the load on all nodeswill increase significantly. In this case, the heating rate will be much lower. As for power surges, they can easily disable 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 to purchase 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 will not equalize the indicators, it will be able to turn off the power in time, preventing overloads on the magnetron.
Some tips on choosing and purchasing microwave ovens
First you need to decide what functions are needed in the microwave. After all, if the owner does not use convection or a grill, it makes no sense to overpay for them. The choice of model should be started not in the store, but behind the computer monitor - this will save you from the annoying imposition of one or another microwave oven by the sales assistant. Indeed, it often happens that a person acquires something completely different from what he originally planned.
When 3-4 models are selected, you can move to the store. The packaging of the purchased goods must not be damaged. Chips, scratches or dents on the microwave body are a reason to refuse a purchase or purchase it at your own peril and risk, but at a much lower cost, since such a product should be classified as discounted.
You should carefully study the documentation accompanying the technique. We are talking about certificates of conformity and quality. Be sure to clarify the period of warranty service and make sure that the seller puts the date of sale, the signature and seal of the store in the coupon. The check must be kept. Otherwise, in the event of a breakdown, repairs will have to be made at your own expense.
Video tutorial on choosing a household appliance: what to look for
For those who are already thinking about purchasing a microwave oven, a very informative video is offered, which will describe in detail what you should pay attention to when choosing such a household appliance. After all, it is always easier and clearer to perceive information by ear than to get acquainted with it in printed form.
Final part
The microwave oven is indeed a great helper in the kitchen. However, in order for it to last for 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 free from such problems, you can not worry about its performance. This means that we can draw a logical conclusion that durability is more dependent on the owner and his attitude to household appliances.
