Power MOSFET or as it is also called "metal oxide semiconductor". Three-layer structure of the transistor Metal - Oxide - Semiconductor. It has a number of advantages over bipolar transistors. These properties are expressed both when the transistor is operated in linear mode and in switching mode.

Main Advantages of MOSFETs

• Instant switching;
• No secondary breakdown;
• Safe operation is characterized by a wide area;
• High gain.
• Higher input impedance.
• Small power consumption.
• When laying out integrated circuits using MOSFETs, a relatively small number of operations are involved than with bipolar transistors.

MOSFET Applications

Use in the design of high-frequency switching power supplies as discrete components, in inverter conversion devices and speed controllers of various types of electric motors. Their use in the design of high-frequency generators used for induction heating, in ultrasonic generators, sound amplifiers and peripheral devices for computers. The use of transistors in speed controllers is limited to low voltage (connected to batteries) and low power, because the silicon surface is able to withstand high off-state voltage and low on-state drop.

MOSFET Operation

The principle of operation of the device depends on the change in the electric field in the semiconductor, the polarization of the insulated gate occurs. This action gave rise to the name of the element, as "metal oxide semiconductor". It is a device in which silicon dioxide SiO 2 was used for the manufacture of the gate, for modern MOSFETs, polycrystalline silicon is used as the material for the gate. There are two types of MOSFETs. The former have hole conductivity - p-channel. Transistors with electronic conductivity are called n-channel. The channel in these semiconductor devices can be depleted or, on the contrary, enriched with carriers.

Rice. No. 1. Basic structure of a MOSFET with hexagonal topology. A positive source terminal with respect to the drain creates current flow through the middle of the source cell via a forward biased p — n -transition. The reverse direction of the transistor is typical for the operation of the rectifier on p — n -transition.

The main characteristics of the transistor

• Control voltage: ensuring the conduction and blocking of the component;
• In the open state (conductive), it is characterized by internal resistance and the maximum allowable direct current.
• In the closed state (non-conductive), the transistor is characterized by the maximum allowable voltage of the direct type (more than 1000V).
• The use of such transistors in speed controllers allows you to operate at frequencies up to several hundred kHz.

Main types of MOSFETs

1. The induced channel transistor, considered the dominant element in the latest integrated circuits. The device is characterized by a positive threshold voltage, from 0.5 to 1 V.
2. MOSFET with built-in channel

Induced Gate MOSFET

Rice. No. 2. a) the structure of the MOS FET with an induced channel. b) graphic image.

MOSFET with built-in channel

Such a device has a non-zero current value, called the initial value, while the voltage has a zero value. Operates in the mode of depletion and enrichment.

Fig. No. 3. MOS FET with built-in channel: a) transistor structure; b) graphic image.

High Power MOSFET Safety Precautions

When testing MOSFETs and mounting them in a circuit, care must be taken. Although the large capacitance allows you to absorb static discharge, it can still damage them. When working with high power MOSFETs, certain rules must be followed.

• It is necessary to keep devices in a special conductive and antistatic container.

• Excessive voltage can break through the gate-source oxide layer, which will lead to cell failure.

  The gate-to-source transient voltage having a negative direction appears in the presence of the startup isolation transformer inductance, the inductance well separates the gate from the trigger circuit during the transition. The junction voltage under these conditions exceeds the gate voltage, which also leads to failure. To solve this problem, it is recommended to use, it prevents the gate-source voltage from exceeding the permissible values. Another effective solution to counter failure is to reduce the gate circuit impedance to the smallest possible value, just to maintain the gate-source voltage rating and keep transients at a level that does not cause accidental turn-on.

  The Zener diode fixes the level of positive transition processes, it automatically fixes the transient processes acting in the negative direction, limits them with its voltage drop having direct conduction.

  Basic rules for using high power MOSFETs

  1. Beware of drain-to-source voltage surges that occur during switching.
  2. Peak current must not be exceeded
  3. It is not recommended to work at an average current value above the normalized value.
  4. It is advisable to stay within the specified temperature limits.
  5. Be sure to pay attention to the topology of the circuit.
  6. Care must be taken when using an integrated body-drain diode.
  7. Extreme care must be taken when comparing the norms of current values.

  With enormous advantages, high power MOSFETs, when used correctly, serve to improve the design of the system, which, with fewer elements, can be better, more compact, more functional than similar devices, but of a different layout and type.

  Write comments, additions to the article, maybe I missed something. Take a look at , I will be glad if you find something else useful on mine.

Now the court is considering a dispute between the management company "VB-Service" and their client - the company "Bogazichi", which decided to challenge the bill for the maintenance and repair of common areas. According to existing practice, the amount for these services of the management company is approved at a meeting of owners and then charged for each meter of real estate that is in personal ownership (area of ​​an apartment or office).

“At the general meeting of owners, a tariff for the maintenance and repair of the MOP was approved in the amount of 1,500 rubles. for 1 sq. m. UK through simple calculations, multiplying this tariff by the area of ​​the premises of the owner and the number of months for which he collects money, presented the court with a corresponding calculation. Representatives of the owner objected, pointing out that if the tariff is multiplied by the area of ​​the owner, then the payment for the maintenance and repair of personal property, and not the MOS, will be obtained. In order to calculate how much money each owner owes for the MOP, it is necessary to determine his share in this MOP (this is also indicated by the Housing Code of the Russian Federation in Articles 37 and 39). With this approach, the cost of maintaining and repairing the MNP for a particular owner is reduced by 7-9 times (depending on the number of square meters of the MNP in each specific case),” says Mikhail Kyurdzhev, partner of the A2 Law Office, who defends the interests of Bogazichi in court.

According to him, it is fair to use the following scheme. If the area of ​​\u200b\u200bthe house is 10 thousand square meters. m, the area of ​​all apartments is 9000 sq. m, and the area of ​​​​the MOP is 1000 sq. m, then the owner of an apartment of 90 sq. m, it is necessary to determine its share, both in the area of ​​\u200b\u200ball apartments, and in MOPs. Accordingly, the entire calculation can be represented as a simple mathematical proportion: 90 relates to 9000 in the same way that X relates to 1000. Thus, the area ratio is 1 to 100, which means that the owner of an apartment of 90 square meters. m should contain 10 sq. m MOS. And it is 10 sq. m must be multiplied by the cost of the tariff, and not 90 sq. m, as suggested by the Criminal Code.

Dangerous precedent

As Kyurdzhev noted, the new case could become a precedent that will cause a wave of similar claims, both in residential and commercial real estate.

The courts of first and second instance supported Bogazichi and reduced the amount of the penalty by more than six times - from more than 5 million rubles. up to 950 thousand rubles. However, the decision was overturned on appeal. Now the company is preparing to protest it, said Kyurdzhev.

In turn, the VB-Service company stated that the recalculation requirements were completely unfounded.

“A gross violation of the law was committed in the court of first instance, everything was corrected at the cassation.

No precedent has been set. We don’t know if Bogazichi is going to the Supreme Court, but I’m sure that there will be a similar decision,” Gazeta.ru was told in the legal service of the company.

Lawyers assess the prospects for further development of the case in different ways.

“The arguments of both parties, both the owner and the management company, in fact, boil down to different interpretations of the same articles (37 and 39) of the Housing Code of the Russian Federation, the wording of which is really quite difficult to understand and can often be interpreted differently. The level of expenses for the maintenance of the MOP directly depends on the share of the area owned by the owner himself, and both sides agree on this, but the owner points out that he should pay less, based on the fact that the calculations of the Criminal Code are based on an erroneous interpretation of the proposed legislative framework”, - says the head of the dispute resolution practice at IFC Horizont Capital.

In his opinion, the interpretation of the owner in this situation looks more correct, and the arguments given are more weighty.

However, it is not yet clear whose side the court will take, especially since in the event of a choice in favor of the owner, a precedent can be created that will affect the entire sphere of relations between homeowners and management companies.

“The court will definitely take such consequences into account,” Itskov is sure.

UK will be put under the knife

The head of the "School of a competent consumer" project believes that if a mass transition to a new calculation system begins, the consequences for the real estate management system can be very sad.

“This is the wrong approach. It is possible to reduce the fee by 10 times, but it is stupid to demand from the Criminal Code that they do full work for this money. They just turn around and leave. To reverse the current system is to recognize that houses should not be managed at all. In fact, we will put all the Criminal Codes under the knife. But we are entering winter, the heating season is starting,” he says.

In his opinion, the current practice of calculating payments based on the area owned by customers is completely legal.

“There is a general rule that the owner bears the costs in proportion to the share of the common property. But the share of his property reflects this proportion. It is almost impossible to calculate it exactly. How to add flights of stairs, general communications and roof area? Kozlov asks.

The head of the legal support department at NP ZhKKH Control also believes that the existing methodology for calculating the payments of the Criminal Code is fully consistent with the law.

In turn, Kyurdzhev is sure that the new practice will not harm the Criminal Code in any way.

“We managed to look into the financial performance of the management company, the difference between the money they collect and the cost of services is huge. So if you reduce payments by six times, there will still be enough money left, ”the lawyer said.

The President of the Society for the Protection of Consumer Rights Mikhail agrees that the requirements to calculate services according to the new methodology are completely justified.

“These questions come up all the time. In my opinion, it is absolutely correct that they are asked to pay based on the share in the common property, and not on the footage. No questions arise here; if the owners are consistent in defending their rights, they will win the case,” he said.

According to the head of the OZPP, after a precedent is created in court, other similar claims may arise. “Tariffs are constantly recalculated, but thus payments for the maintenance of common areas have not yet been considered. It is quite possible that now this area will be monitored more closely,” says Anshakov.

Regular wet cleaning in the house is a guarantee of good health and normal well-being of its inhabitants. It seems that everyone knows and understands this very well, but no one likes to wash the floors, and the main reason for this is the antediluvian inventory, which is still used in many homes. However, manufacturers of household goods have long offered a great alternative to creepy floorcloths - mops. Today we will find out what a mop is, what types it is and what are its advantages over conventional items used for wet and dry cleaning.

Mop or nozzle for her?

First, we need to clear up some of the confusion resulting from the misinterpretation of foreign terms. Modern cleaning equipment, which we used to call nothing more than a mop, is actually called a flooder in specialized circles. This is the definition given to mops with a flat holder for cleaning floors, walls and glass surfaces. What is a mop? This term is usually called a nozzle that is attached to the flooder. Despite the fact that the English word mop, the translation of which sounds like “mop”, has no other meanings, in our language it is customary to mean not a mop, but only its element.

Surely such confusion arose due to the fact that there is another type of mops, a little outlandish for the inhabitants of our country - this is an inventory consisting of a stick and a nozzle made of long twisted ropes. Such a cleaning device is called a mop mop. Residents of Western countries have been using them for more than a dozen years, while they are common not only in the everyday life of ordinary housewives, but also as working equipment for cleaning professionals. A little further we will understand in more detail the varieties of all these cleaning devices, and also describe their main differences and features.

In general, we have already answered this question, so now you can start discussing household inventory for cleaning in more depth. A mop is an improved floor mop. Usually, rags are used for these needs - old towels, clothes, etc., sometimes - special microfiber floor cloths. But both of them are not very convenient to use, because such rags constantly strive to slip off the mop, do not always absorb water well and often leave stains on the floor.

On the contrary, a mop is a rag of a special design. It cannot even be called a rag, as it does not look like a single piece of woven fabric. The surface of the mop consists of long thick fibers - these are twisted cords, which are sometimes folded and curled into continuous spiral loops, and sometimes cut in the middle. For the manufacture of such nozzles, several types of materials are used, most often it is cotton, acrylic or microfiber.

Types of flooders

Modern mops, first of all, are divided into flat and with a wringing mechanism. The latter are a foam roller with a relief surface attached to a strong handle. The base of such a mop can be metal or plastic. Excess liquid from the foam sponge is removed using a special squeezing mechanism. It is arranged very simply - there is a handle at the bottom of the mop, which, when lifted, sets in motion two slats that wrap around the roller along its entire length and squeeze water out of it. Thus, hands remain dry and clean while mopping, and the cleaning process is easier and faster. Plastic mops tend to be significantly cheaper than metal mops, but they are not as durable as their expensive aluminum counterparts.

Flat mops are arranged a little differently. They can also be plastic and metal, the handle of the device is usually telescopic (it can be extended if necessary), and the holders differ in their functionality:

• rotary;
• static.

And in form:

• rectangular;
• triangular;
• trapezoidal.

And for the purpose:

• for wet cleaning;
• for dry cleaning.

A mop can be attached to the floater with threads, pockets or straps. Threaded connection is used in rope mops.

Types of mop

We have already figured out what a mop is, now let's figure out how their different types differ from each other. As we have already mentioned, the mop attachment can be a rope one. In this case, soft cotton flagella, which absorb water well and are easy to wring out, are gathered in a bundle on a threaded plastic mount that is screwed onto a holder stick. Such a mop is very convenient to use, with its help you can easily wash the most hard-to-reach corners in the apartment, and due to the fact that the washing element itself is not a continuous sheet, but a lot of ropes, it copes well with dirt in the crevices, seams between the tiles and on thresholds.

Mops for flat mops are rectangular and trapezoidal, triangular rags are less common. They are designed specifically for washing corners. According to their texture, mops are also not the same: the thickness and length of their villi may differ. Often, manufacturers combine materials during the manufacture of nozzles, for example, by rubberizing some elements so that the mop quickly and easily cleans heavy dirt or by adding acrylic fibers to them, which attract dust to themselves. The size of the mop is selected depending on the size of the floater. Usually, all manufacturers standardize their products and produce mop heads from 35 to 100 cm long.

What to hold on to

It is important to be able to correctly select not only the mops for cleaning directly, but also the mop itself. As a rule, the nozzle wears out over time, the cotton fibers “wash out” and become thinner, because of this they do not remove dirt from the surface as they should. Synthetic mops, under heavy use, are also not very durable. However, when the rag wears out, this is not a reason to get rid of the entire mop, just change the mop, leaving the old flaunder and stick-holder, which is also called a cue stick.

Saving on a stick is not worth it, if you buy the cheapest model, it is unlikely to serve faithfully for several years. Most likely, at the slightest strong pressure on the mop, it will bend or break and the inventory will become unusable. Therefore, it is best to purchase aluminum or high-quality plastic sticks. Some manufacturers offer models with multi-colored markers. This helps not to get confused in the inventory, which is especially important for those who clean residential and utility rooms with different rags.

Rag care rules

In order for the mop to serve the hostess as long as possible, you need to properly store it. So, wringer mops with a foam roller are usually kept in a bucket of water. This prevents the porous sponge from drying out and crumbling. If the foam rubber hardens, then it will have to stand in water for a long time in order to regain its elasticity and suppleness.

Flat mops, on the other hand, should be washed thoroughly after use and dried well without being thrown away. Otherwise, the fibers will rot and become unusable. If you often leave the mop wet and store it crumpled, and even in a bucket, without access to air, it will soon acquire an unpleasant smell, which will remain in the room after cleaning.

Additional cleaning equipment

Cleaning is facilitated by the use of not only mops, but also special buckets. For round rope nozzles, there are containers with spherical "colanders", with the help of which it is much easier and faster to wring out a rag. Such a bucket is divided into two compartments - the first is designed to dip a mop into it, and on the other side, excess water is squeezed out of it.

For rectangular flat mops, you also need to prepare a special container. It should be of a special shape and fit the size of the floater.

mop manufacturers

In wide access for buyers, as a rule, Chinese products are presented. They are inexpensive, usually in the range of 200-350 rubles. Domestic and European mops are more expensive. Some models are priced at 1,000 or more rubles. Such a high cost is fully justified, because such equipment will last in the house for more than one month and even more than one year. The most popular among buyers are products of Italian, German and Polish manufacturers, including Spontex, VILAND, Vileda Professional, APE and others.

If you ask yourself how MOP stands for, then on the World Wide Web you can find a lot of definitions. It turns out that the abbreviation MOP is both the junior and (attention!) Ministry of Defense Industry. There are a dozen more serious and not very organizations and places designated by this short word, but a modern hostess will answer the question of what a mop is in a completely different way.

Agree, even for a zealous adherent of perfect cleanliness, the need to use a floor cloth causes a feeling of some disgust and a subconscious desire to postpone wet cleaning the next day. But progress does not stand still: thanks to the mop cloth, this unpleasant procedure has become much more comfortable and effective.

Mop: a brief description, history of occurrence

A mop is a tool used to clean floors. It may consist of a bundle of rope or a piece of cloth, sponge or other absorbent material hinged to a handle.

The word "mop" (English mop) appeared in English in the middle of the 15th century and meant nothing more than a mop. The first homemade mops were primitive products, where old pieces of fabric cut into strips were attached to the handle with the help of the so-called "mop nail" (a long nail with a wide flat head).

The evolution of the mop from a doormat to a high-tech product

Since that time, mop has undergone many changes and improvements. So, in 1837, the American inventor Jacob Howe created a mop holder, in 1893 Thomas W Stewart patented his version of a yarn well mop, and also developed a clip that allowed changing its washing part.

In 1950, Thomas and Peter Vosbikian (Piter & Tomas Vosbikian) received a patent for a sponge mop, which became the prototype of mops of our time. This design used a lever and a flat strip of metal to squeeze out the mop. In 1999, Scotch Brite suggested using natural cellulose as the cleaning surface of the mop, which, unlike ordinary cloth, does not leave lint on the surface being cleaned.

As you can see, the modernization of the mop continues, but at the same time, all flooders are structurally almost unchanged, they consist of four main parts: the mop head, replaceable cleaning material, handle and mechanical fastener that connects them.

The sequence of application of different types of mops for cleaning

To get the perfect result, cleaning companies consistently use several types of mop. The first step in cleaning is to use a vacuum cleaner or dry mop (dry-mop), made of yarn or microfiber-based fabric and designed to collect dust, sand or other dry dirt. After getting dirty, these mops are perfectly cleaned in the washing machine.

At the second stage, wet mops (wet-mops) are used, which are strips of microfiber fabric or a bundle of twisted yarn ropes. They serve to clean grease, dirt, as well as to remove excess water or other liquid from the floor.

Then use pre-moisturizing mop - these are flat microfiber-based mops that are pre-moistened with a solution of detergents and do not require large amounts of water. They are attached, as a rule, with Velcro, thanks to which they can be quickly replaced, and do not leave puddles on the surface.

After that, cut end mops are used, consisting of cotton yarn with cut ends. As a rule, they are inexpensive, and it is not recommended to use them after contamination.

Loop end mop is a cleaning tool that, unlike a trimmed one, has a loop at the free end. It captures a larger area of ​​the treated surface, can absorb more water and lasts a little longer.

Finally, microfiber mops based on polyester and polyamide. During use, they retain the dirt being removed from the surface inside until rinsed out and can hold more water than any other type of mop. At the same time, they can be washed more than 500 times, which does not affect the properties and characteristics of the material. The use of microfiber mops requires fewer chemicals, making them considered environmentally friendly.

Mop marking

For a number of premises (hospitals, schools, kindergartens, etc.), in order to protect people with a weakened immune system from harmful bacteria, increased requirements for cleaning thoroughness have been established. In this regard, there are standard color coding systems for marking mop according to their possible places of use.

Red is for high risk areas such as toilets and urinals. Yellow ones are designed for cleaning laboratories, educational institutions, cleaning sinks and mirrors. Blue is used for universal cleaning. Green markings are put on mops that serve to maintain cleanliness in public catering facilities, such as kitchens, canteens, and restaurants.

For domestic needs, mops are classified according to two main criteria - for wet or dry cleaning.

Mops for wet cleaning

Wet mops usually have a sponge or cloth backing and are used to clean kitchen or bathroom floors with detergents. At the end of cleaning, they are perfectly washed out with running water, while wet mops should be well dried for storage between cleanings.

Mops for dry cleaning

Dry mops are sometimes referred to as dust mop. They feature a large flat head and a swivel, making it easy to get into any hard-to-reach places. A dry mop can be cleaned by simply shaking it in the open air, and if it is especially dirty, it can be soaked overnight in soapy water or washed in a washing machine.

So, if we define a mop, then this is a modern cleaning tool that allows you to quickly and efficiently carry out both dry and wet cleaning of the premises, making this work easy.

Word mop comes from English mop“, which in translation means a mop. However, in Russian, the word mop means a washing nozzle or, in simple terms, a rag for washing the floor, worn on a mop holder or a floater. The very concept of “mop” is not used in professional slang for cleaning workers. The “Soviet” mop is a metal or wooden handle with a rag wound or clamped with a rag from trimming a canvas-stitched fabric. A modern mop for washing floors is collapsible, consists of three components:

Lever usually aluminium. It is also made of stainless steel, wood, fiberglass, plastic. At the end of the handle there is a hole for the latch or a thread.

1. Mop holder or floater. It is usually made from impact-resistant plastic. It is attached to the handle with a hinged lock or screwed onto the thread. The two most common types of holder are the clip holder (suitable for Kentucky-type rope mop and cut-away nonwoven cloth) and the flat holder with different types of mop attachment, which we will discuss below. The term flooder is generally applied to mops with a flat mop head.
2. Mop. It is made from cotton, microfiber (microfiber) or a combination of materials with some additives, depending on the purpose of the mop.

The first special mops that appeared, and not fabric scraps, are considered rope noodle mops Kentucky type. They were first used in the 15th century by conquistadors to wash the decks of ships. Rope mops are inexpensive, but very inconvenient to use and ineffective. In fact, they carry mud, which is acceptable on the deck of the ship, when the mud can be thrown into the sea. The contact spot (the place at the base of the mop, with which we press on the floor and wash it) at the rope mop 25-50 sq.cm. Flat mop floaters have a contact patch 10 times larger because the force is distributed over the entire base area of ​​the floater.

Used for dry floor cleaning cotton mops with woven fiber. The microfiber dry cleaning mop is excellent at attracting dust, but does not absorb moisture, so it must not be crossed with a scrubber dryer, because after passing such a mop along the trail of the car, all the garbage will remain at the intersection. A mop with such a mop, 60 to 100 cm wide, is pushed in front of the cleaner. Cotton perfectly absorbs moisture, the wicker structure collects and sweeps debris, after dry cleaning, the cotton mop is vacuumed. For wet cleaning, a cotton mop is used for especially dirty work, because. it wears out quickly and smells bad. At the same time, the special weaving of the mop threads for the mop allows you to sweep and wash at the same time.

For daily wet floor cleaning As a rule, microfiber cleaning nozzles are used. They are more durable and do not rot. Microfiber mops with microfiber about 15 mm long are universal, they are used more often for washing floors after entrance areas. Microfiber mops with a combined height of microfiber are used for washing tiles (it washes the seams well). Mops with microfibre less than 7 mm are used for wiping the floor dry, for washing floors demanding moisture, such as laminate and parquet. Wet cleaning with a mop with a mop occurs moving backwards, moving the mop along the Z path.