Network filter - what is it? Network filter for computer. Purpose and Selecting Network Filter Filter for Large Loads Characteristics

If you say at all simple languageThe network filter is such a tee with a switch, very often used to connect the computer to the power grid. This device You can meet on the shelves of electrical stores, as well as already connected to the outlet in apartments and houses. But why do you need a network filter and what's special in it? We will talk about it further.

Purpose of the mains filter

It is known that you have a network in the outlet alternating current Voltage of 220 volts. "AC voltage (current)" means that its value and / or a sign are non-permanent, and change over time on a specific law.

The nature of generating electrical machines (generators) is such that on the weekend terminals, the EMF of a sinusoidal form is generated. However, everything would be fine if all devices had a resistive nature, there were no launchers, and did not have impulse converters in their composition. Unfortunately, it does not happen, because Most devices are inductive, capacitive, brush engine, pulse sources of secondary power. All this intricate set of words are the main perpetrators of electromagnetic interference.

We started an article with speech about electromagnetic interference not just like that. These interference "spoil" the smooth form of sinusoids. The so-called harmonics are formed. If we decompose the real signal from the rosette in the form of a Fourier series, we will see that the sinusoid was supplemented with various functions, different frequencies and amplitude. The voltage form in the real socket has been far from ideal.

So what is the result? Poor power supply is a problem for radio transmitting devices. Simply your TV or radio will work with interference. In addition to interference from consumers, there are no obstacles of random origin that we cannot predict. These are bursts, from power supply interruptions, inclusion of powerful load, etc.

The network filter is needed in order to:

1. Filter interference for clean device nutrition.
2. Reduce interference emanating from the supply devices.

How does a network filter

Filtration of unnecessary components is carried out, oddly enough, with special filters, they are collected from inductors (L) and capacitors (C). Restriction of bursts high voltage - varistors. This works due to such electrical concepts - time constant and switching laws, reactive resistance.

The time constant is the time for which the capacitor is charged or the inductance is accumulating. Depends on the filter elements (R, L and C). Reactive resistance is the resistance of elements that depends on the frequency of the signal, as well as from their nominal. Present in inductance and capacitors. Conducted only to transmit an AC power to an electrical or magnetic field.

Simple words - with the help of reactive resistance can be reduced, limit the high-frequency harmonics of our sinusoids. It is known that in the outlet of the frequency of 50 Hz. So you need to calculate the filter on frequency is much higher and more. In inductance, resistance grows with increasing frequency, the condenser is falling. That is, the principle of operation of the network filter is to suppress the high-frequency components of the network sinusoid, while having a minimal effect on the main 50 Hz component.

We look inside

We figured out where the network filter is applied, so now let's deal with what a real network filter consists, we abstract on the theory.

1. Filter interference.
2. Button or toggle switch.
3. Varistor.
4. Socket group.
5. Network cord.

The insides of the expensive and high-quality filter, pay attention to the capacitor battery on the right and the dimensions of the choke in the center:

Let's go in order - the filter. The design of such an element is an LC filter. Zero and phase wires from the outlet will be connected to the inductance coil (each to its own), and between them 1 and more capacitors. Model nominal details:

• the inductance of each coil is 50-200 μH;
• capacitors 0.22-1 μF.

The varistor is a semiconductor element with nonlinear Wah. When a certain voltage applied to it is reached, protects the load by a short-term short circuit of the input circuits of the power supply, taking "hit" on itself. Need to save your equipment from "bad nutrition". The most often used varistor for 470 volts. The principle of action of such protection is obvious - when the voltage buckets of the supply circuit of the protected load are spoiled by a varistor.

The contents of a cheap filter, there is no throttle at all - its effectiveness is minimal, but still there is a varistor (blue in the center of the frame), and it will save from voltage jumps:

Why do you need a toggle switch if everything can work without it? It just so that you do not jerk each time the plug out of the outlet, because, most often, stationary equipment is connected via the power filter. This will reduce the wear of the contact plates of the socket.

Network filter schematic diagram:

Where the filter is applied and what to do if it is not

The fact is that in high-quality power blocks, it must be installed, directly on the board and especially on high power BP, such as computer. But, unfortunately, your chargers for smartphone, BP from a laptop, EPRU of luminescent and lED lamps Most often do not have them in their composition. This is due to the fact that chinese manufacturers Simplify the schemes of their devices to reduce their cost. It often happens that there are places for details on the board, the purpose of which to filter interference, but they simply are not smoking and there are jumpers in them. Computer blocks are a separate topic, the scheme is almost one, but the execution is different, and there is no filter in the cheapest models.

You can reduce the interference of your TV or another device that you want to protect and improve the properties of its power supply adds the usual extension with such a filter. It can be collected or extract from a good, but unnecessary or defective BP.

With the development of technologies, the number of useful devices is growing, without which it is already difficult to present their lives. Today, all household appliances and gadgets must be connected to the power grid for permanent operation or recharging, so the need for a large number of sockets is constantly growing. Network filters are equipped with short-circuit protection, individual or common switches. In addition, advanced and expensive models filter high-frequency interference, which are formed due to the large number of connected to electrical network devices and bad, old wiring.

How it works?

Network filter, depending on the cost, performs the following functions:

1. Protection against short circuit;

2. Filtering high-frequency interference;

3. Protection against short-term voltage pulses.

Short circuit - condition electrical chainWhen the phase and zero are connected directly without load. Those. If somewhere open the wire, if something in some kind of device is closed, the network filter must be cut down and protect the remaining equipment.

Interference - the consequence of the operations connected to the network. Almost all electronics are now on pulse power sources - televisions, computers, etc. Pulse power supplies inevitably give interference to the network. In addition to them, there is no interference with inductive load devices, such as a refrigerator.

High-frequency interference is not harmful by electronics, but they affect her work. For example, foreign sounds may appear in the audio engineering, on the analog TV or ripple monitor and distortion monitor.

Voltage pulses occur due to connecting to the network of any reactive load, again the refrigerator, welders etc. So that it is not burned by anything, the Network filters put the Barrots that absorb these Imuls. But from the long exposure to high voltage, they rarely protect.

Types of network filters

For example: when connected to a PC and peripherals to the network filter, it will work without complaints, since the power of consumption in these devices is low. But if you plan to use a network filter in the kitchen, connect an electric kettle, plate, water heater simultaneously, then with simultaneous operation of all devices, the filter will turn off.

Protection levels

According to the degree of protection, network filters can be divided into:

1. Basic protection level (Essential). Such filters have the simplest (basic) protection. With voltage pulses, they take a blow to themselves, are characterized by no high cost and simplicity in the design. Apply them better with inexpensive and low-power equipment. Serve an alternative to ordinary extension cords.

2. Advanced protection level (Home / Office). Suitable for most instruments in the house and office, are presented on the market with a wide range near and loyal value in relation to quality.

3. Professional protection level (Performance). It gives almost all interference, it is recommended to purchase for an expensive interference technique. Network filters with a professional level of protection are more expensive at cost, in contrast to the previous ones, but their reliability is completely paying for costs.

Protection against short-term jumps / voltage pulses - Almost all filters are equipped with this function, the principle of its action lies in the absorption of short-term freaky impulses. From a long high voltage, it does not protect. If in your house most of the time is increased or reduced voltage, then it is better to give preference to the stabilizer, since the network filter will be useless.

Turning off when overheating - The overheating sensor is responsible for shutdown, with an increase in temperature above the maximum allowable network filter is de-energized. When using a filter near the heating devices or at maximum power consumption, the overheating sensor helps to avoid damage or the occurrence of dangerous situations.

Interference - In Russia, the electricity supply frequency is 50 Hz, but also there are additional high-frequency harmonics on the network. The filter eliminates high-frequency "dirt", reduces it to a minimum, thereby leaving a clean 50 Hz sinus without unnecessary harmonics.

Switch

Network filters are equipped with a switch to constantly not pull the plug from the socket, the switch protects the time and is safe to use.

Switches are found in several types:

Extra features

Indicator - informs about the inclusion of the network filter, is often combined with the switch button. Depending on the model, it may be common or individual for each network filter outlet.

Mounting on the wall - Some filters are equipped with loops on the reverse side. This supplement is designed to reduce the risk of damage to the wires, simplify cleaning. The network filter is conveniently fixed to the wall or to the inside of the computer table, the wires will not interfere under the legs.

Fastening for wires - you need if the filter is connected a large number of Devices prevents the wires of the wire.

Some computers are connected to the network directly through the outlet. All specialists in one voice argue about the inadmissibility of such actions due to constant voltage jumps on the network. To protect the personal computer from these unwanted overloads, you need to use network filters. Depending on their type, they are able to remove voltage jumps. The processor is capable of listening to many years and not burn. Additionally, the connected speakers, monitor, printer and other devices are removed for the computer.

Externally, the network filter resembles a conventional extension, consisting of sockets and switches. However, it is able to smooth out jumps and remove the interference that is formed on the network.

Why do you need a network filter?

Many are asked about the network filter: "What is it and why is it intended?" To do this, you need to get acquainted with the theory. The current passing through the network of the house is variable and classified as sinusoidal. This name happened from the word "sinusoid", which looks like a wavy line. The voltage in the network, as well as the wave, is constantly decreasing and increasing. Smooth oscillations occur from -300 to +300 volts.

If you look after the current parameters in the outlet, you can see sharp jumps and large voltage amplitudes. All these impulses are able to make household appliances in the apartment completely unsuitable for further operation. Most often, audio centers are suffering, televisions and, of course, computers.

How to choose a network filter?

To protect the computer in the house you need to select a high-quality network filter. The price of a conventional model ranges in the area of \u200b\u200b100 rubles. However, they cannot guarantee a high degree of protection. personal computer. Racing on the network sometimes occur pretty high, so you need to choose a more powerful network filter. "What is it and how to choose it?" - A question that interests many.

The cost of such an appliance will definitely be higher than 100 rubles. When choosing a network filter store you need to familiarize yourself with its parameters specified by the manufacturer on the package. As a rule, it is said about the length of the cable, the pulse interference voltage, the maximum limiter, as well as the number of available sockets. The cable size must be chosen on the basis of the conditions in which the computer is used. If it is far from the outlet, you should envisage and select a larger cable. The main thing in this matter is to hide it reliably. Needless to say, the cable damage can lead to a short circuit in general house. Also, if you pour something on it, it will lead the system to the failure. Considering all of the above, it is better to choose network cable larger and install it closer to the wall. In this case, access to it should be limited. With the help of the stationery clamps, the remains of the cable must be collected and fix together. In this case, it will take at least a place and can be absolutely safe. Manufacturers usually produce cables from 2 to 5 meters. In most cases, this is enough to connect all devices. The pulse interference parameter is in the range of from 3500 to 10,000 A. The best network filter will have a high indicator. When buying a network filter, you need to pay attention to the maximum current of its current below 10 A.

Causes of voltage jumps

There are a large number of reasons that, ultimately, lead to a sharp undesirable jumps on a network filter. "What is it and how to deal with it?" - A question that interests many. First of all, they are caused by the use of electrical receivers. With frequent use, overload occurs, and the voltage starts to ride. The second most common cause is no longer associated with human activity. We are talking about atmospheric overvoltage. Unfortunately, the weather makes their own adjustments and you have to be considered. Additionally, jumps can occur due to failures in work as a rule, short circuits occur in them, which lead to complex processes. All this finds its display in the work. shared network at home.

Wipes in the network

Network fluctuations are a complex function. It can be represented as a variety of sinusoid. Each of them has its own frequency. IN general System It defines a specific amplitude, so sinusoids together form a wave. In order for the tension to be stable, only one sinusoid is needed, which has a frequency of 50 hertz. In this case, the amplitude will be at the mark of 310 volts. The task in this sense is to eliminate all other sinusoids that affect the network. To do this, they need to in every way to suppress and block access to the electrical acceptor.

Aperiodic interference

There are also aperiodic interference that affect the voltage in the system. Unlike sinusoid, they are difficult to predict and block them. In general, the aperiodic interference leads to impulse throws. In the system, they arise and subsidize for a very short period of time. Many network filters are able to cope with such jumps and suppress them.

How is a network filter?

Resistors are not connected with the type of current that runs on them. However, inductance greatly feels the effect of voltage frequency. It is all about the container. When a current is fed to the coil with a high frequency, then its resistance is continuously growing. This effect is called inductive and ultimately, it is brought as a basis for the production of network filters. As a result, it is able to cope with the sinusoids of small and large periods, which lead to high-frequency interference. Two coils use for the best effect. They equally take care of the sinusoid. One coil is in a zero conductor, and the second is in the phase. Depending on the model of the network filter, inductance is different. One coil is able to withstand from 50 to 200 μH.

Low frequency interference

Another problem is the interference that coils also use to suppress them, but already with active resistance. Additionally, network filters can be equipped with several resistors that are able to make a significant load. However, it should be borne in mind that the resistance parameters of the resistors should not be at a high level. This is due to the general system. When the resistor has high resistance, the voltage in the network will fall significantly. On average, manufacturers produce them with parameters of 0.5 ohms. The main thing is that this indicator does not exceed 1 ohm.

Filter APC P5BV-RS

A network filter for a computer APC P5BV-RS can cope with pulses that can be caused by lightning strikes. Any overvoltage always leads to a sparrel of a computer, and as a result, all the information from it will be removed permanently. The APC P5BV-RS network filter is able to successfully suppress minor pulses on the network, which, ultimately, also affect the operation of all devices in the house. The successful operation of the computer can be strongly extended if you immediately install a power filter. APC has long started its development in the field of pulse suppression of different frequency. To date, it has become possible to even remove interference related to the telephone network. Computers belong to sensitive technique that need to constantly remove from all jumps.

The APC P5BV-RS model has as many as 5 outlets. This is quite enough to connect the computer along with speakers and wireless mouse. Additionally, you can use the remaining sockets under the xerox and the printer. The maximum load current is at the limit 10 A. The frequency of alternating voltage is 50 Hz. Cord length - 2 meters. This is quite enough to establish it in a convenient place and not worry about the safety of the network filter. Additionally, the APC P5BV-RS network filter is equipped with a coaxial line protection. As a result, the filter is capable of coping simultaneously with different jumps. All technology lies in the use of Teleantenna. The filter width is 7 cm, and the height is 3.8 cm with a weight of only 0.7 kg. It should also be noted that APC provides a long warranty period for its products, which speaks of great quality and reliability.

Filter Defender DFS 501/505

The Defender DFS 501/505 network filter is designed to eliminate jumps on the network. All devices of this series have the ability to suppress low-frequency waves and impulse interference. To eliminate jumps with high frequency, a gas discharge is provided. For convenience, the power filter is equipped with two ports to which any gadgets can be connected. Without using a computer, you can easily recharge the player. All devices that are connected are not affected by jumps and vibrations thanks to current protection. Equipped with a Defender DFS 501/505 six sockets. Manufacturers paid special attention to safety, so the network filter body is made of non-combustible plastic. Plus it is shocking. Additionally, protection from children is provided. Protective curtains allow even near young children to safely use a network filter. The socket that is located near the switch is designed only for large adapters.

A distinctive feature of this model is a high level of scattered voltage. Additionally, protection against impulse interference is provided. For convenience there is a special indicator, which indicates the inclusion of the filter, as well as the degree of protection.

Characteristics Defender DFS 501/505

Devices at 220 V equals 50 Hz. The maximum power it can withstand, more than 2000 W. The load current is at 10 A, and the scattered energy - 525 J. possesses this model Three protected chains that act as a stabilizer. The network filter runs from 0.16 to 95 MHz. Plus, it is additionally provided for a fuse, which is installed separately. His advantage is that it is heat-resistant. It also works fully automated, so fails are excluded. The ports in the network filter are capable of withstanding the voltage of 5 V, and the maximum possible current is allowed at the level of 1000 mA. Additionally, these ports provide separate protection, which has a restoring effect and can be used many times.

Model Defender ES.

Defender ES is the best network filter that is able to secure a computer from small interruptions. The advantage of this model is its economy. If in the house where household appliances are used, rarely there are interruptions on the power plants, Defender ES is a good choice. It is perfect for a computer or a simple kettle. The diagram of the network filter is made of non-combustible plastic. All contacts are made of copper. The compactness of this model is good. At a voltage of 220, the device gives 50 Hz, which is not bad indicators. The maximum load that can be used is in the limits of 2200 W. All this is capable of greatly secure a computer from shortwave noise.

Characteristics Defender ES.

Maximum permissible load - up to 10 A. Dissected energy does not exceed 120 J. Poses Defender ES with only one protective chain. Additionally, there is an automatic fuse, which is securely embedded in the switch. The length of the network filter is from 20 to 30 cm. The cords are included in a variety of size: from 3 to 5 meters. Summing up, you can notice certain advantages of this model. Its value is 150 rubles. However, still advise the Defender ES network voltage filter. Ultimately, it is not able to protect the computer from all differentials that happen on the network. Since the value of technology is much higher than the cost of the network filter, do not save on it. It is better to take a reliable network filter of a proven brand and not scared lightning and failures in transformer substations.

MAXXTRO PRO PWS 05K-10F

So, we clarified the question: a network filter - what it is. He interests many. The filter specified in this section is also well suited for computers and laptops. This model can block multiple interference and eliminate most pulses. Additionally, protection is provided from short circuits. In stock led indicator. The body is completely shockproof and is made of high-quality plastic that does not burn. It is also possible to install a network filter on the wall in the room. With large loads, when the diagram of the network filter combines, the contacts are turned off, and the pulse does not reach the device. For greater convenience, 5 outlets are provided. The length of the cord is as much as 5 meters. The maximum load current is at the level of 10 A.

Many believe that a network filter for a computer is a conventional extension with a large number of outlets, as a rule, from 4 or more. This is not true.

In fact, the network filter is a device that is intended for a computer from pulse and high-frequency interference in the 220V electrical network. Therefore, to the question: "Does a network filter need a computer?" You can, without thinking, reply: "Yes, you need."

The article turned out to be volumetric, for it was necessary to consider the following points:

• Introduction: And how to understand without it, why is it and why so?
• Network filter device
• Protection against interference
• You need to know!
• Information for laptop owners only

Why do you need a network filter?

In the household electrical network, although the voltage 220 volts is declared (220V), but it is not always so. This stress can grow smoothly or jump and decrease. Smooth improvements are harmful to computer equipment, especially if it is great increases. At a voltage on the network above 230-235 volts, the computer has "not sweet", it is a bad mode of its operation.

Also harmful and smooth drops of voltage in the network. When the voltage drops in the electrical network below 190-200 volts, computer equipment also begins to work with an increased load.

Still, smooth voltage changes are not as harmful as sharp jumps of voltage changes in both one way (increase) and in the other direction (lower).

Speaking in the language of electrical engineering, jump-shaped voltage changes in the electrical network lead in the computer and in other household appliances to the appearance of the so-called "transition processes". Suppose, the voltage in the electrical network rose sharply by 5-10 volts and then also dropped back to 5-10 volts. It would seem, well, that, because the voltage changes are very small, only 5-10 volts. But it was not there.

The fact is that the sharper the voltage change is happening, the stronger these are the most transients in computer equipment. These transition processes can already cause a voltage jump at 1-2 times inside the computer, more than the initial voltage drops by 5-10 volts.

Why is this happening? This is a kind of inertia, just not in mechanics, but in an electrician. At the entrance, the voltage has rushed a little bit, but in a very short period of time. And at the output, already "inside" a computer "responds" is much stronger jumps.

By the way, probably, you noticed that in trains under the electric sockets 220V it is written that the safe operation of any equipment, except for the electric Rab, is not guaranteed. This is due to the same transition processes.

The train has no alternating voltage of 220V, it is created there "artificially". And alternating voltage in the train varies from + 220V to -220V jumps like (with alternating voltage, the polarity of the voltage with "+" to "-" changes 50 times per second!), Not as it happens in the electrical network at home. This can lead to transition processes in computers and gadgets connected to the electric train network network, and can lead to a device breakdown. This warns the railway of its passengers.

So impulse interference, voltage jumps on the 220V network are harmful to computers, and it is necessary with them. For this serves a power filter.

Network filter device

The design of the network filter provides two "filter" blocks. In the first there are so-called varistors - these are semiconductor devices, the active resistance of which is directly dependent on the voltage. The higher the voltage at the inlet, the smaller the resistance of the varistor.

Suppose in the electrical network 220V there was a sharp voltage jump, it became more than 220V. In this case, the varistors automatically reduce their own resistance, so they take on the "superfluous" energy, part of the "extra" electric current, transforming all this "excess" in heat. This allows you to protect your computer from increasing the voltage in the electrical network.

The second filter block is a capacitive type filter, it consists of the so-called capacitors. Capacitors take out excessive energy, which is highlighted with voltage jumps up, and give this energy back when the voltage jumps down.

Thus, they, as if smoothing the jumps of stress, making them less and, more importantly, much calmer. Up - slower, downstream is also slower. It turns out that instead of sharp jumps, we get smooth "swing", as on the waves, which is much less harmful to computers.

electricitypassing through the network filter, it falls into the computer is pretty smoothed, "purified" from sharp oscillations and drops.

As they say, it was necessary to prove!

With slow voltage drops

If the voltage in the network rises or decreases slowly, then the network filter of this, as it were, does not notice. It does not smooth and filters such slow drops. For this, the network filter is not suitable. There is already a voltage stabilizer.

The function of the voltage stabilizer, as a rule, perform so-called sources uninterrupted power (UPS). These are heavy devices that are sold in computers selling stores. They are really heavy by weight, because their composition includes a powerful battery that is capable of autonomously maintaining 220V power supply with a completely disconnected 220V electrical network.

With increasing external voltage, the uninterruptible power supply automatically reduces its level to an acceptable. With a very strong increase in external voltage, it automatically turns off from the 220V network and moves to work from the battery. Similar to the UPS "Fights" with a decrease in voltage, up to its full shutdown. It increases it to the desired level due to the energy of the rechargeable battery.

Network filter does not know how to do this, it is not intended for this. But some network filters are able to automatically disconnect from the 220V network if the voltage in this network drops below or raises above a certain threshold. As a rule, up is over 250 volts, down - below 180 volts. And this is also a certain protection of computers from breakdowns due to problems with the 220V electrical network. Thanks to the network filter for the computer!

Protection against interference

In addition to voltage drops, in the household electrical network is full of interference. They are impulse, very sharp and short, with an amplitude that gives up to 6000 volts! Such powerful impulses can output very sensitive computers chips.

And there are not strong, but very high-frequency. So high-frequency that these interference can have a direct impact on the operation of computer equipment. The computer can perceive these interference as internal signals, can begin to respond to them, which leads to freezes, stops in operation and other similar failures.

The network filter is successfully fighting with pulsed interference, and with high-frequency interference, smoothing them and turning into absolutely safe voltage drops.

Technical Features of the Network Filter

Most network filter models are calculated for the maximum electric current in 10a. With the calculation of it and the fuse is established. This is enough to connect the PC and it. But it can be completely insufficient if you connect an electric iron to the network filter, microwave, etc. Powerful devices.

You can not connect similar devices to the network filter. No need to perceive a network filter as a banal extension.

Computer, laptop, tablet, TV, router, printer, charging for your phone or smartphone connect to a network filter.

The rest, including irons, heaters, vacuum cleaners, microwave ovens, never connect to the network filter. It is not intended for this!

Why for iron smoothing voltage drops? He will not be better to iron. Or why protect the vacuum cleaner from high-frequency interference, which he himself creates?!

How to choose a power filter for a computer?

When choosing it is worth paying attention to the following points:

• network filter Wire length,
• power button, shutdown with light bulb,
• number of outlets
• do not confuse with the usual extension.

Little About electrical wire Network filter. Standard wire filter wire 180 cm, although there are models with wire for 3 and 5 meters. Models with long wire are more practical. At the same time, if the big length of the wire is not needed, it is better to take a model with a shorter wire. So extra wires will not "hang out" around the apartment or office.

Is there some more turn on and off button Network filter. Very convenient, you can turn on and disconnect the power filter without removing the plug of the power filter from the outlet. Especially if the socket is located in an uncomfortable place, under the table, near the plinth, behind the cabinet, etc.

Yet again Light bulbAn indicative of turning on and off the network filter is also an important and useful detail. Always clearly visible, a network filter is turned on or off. If the computer does not turn on, check it first, whether it is connected to the network 220V! The signal light here is quite by the way.

Number of sockets Network filter is also an important feature. The sockets must be missed for connecting all components of your computer: system unit, monitor, printer, router, scanner, etc. Otherwise, additional extension cords will be needed, it will lead to chaos of the wires. It is better to calculate everything in advance, and choose a suitable network filter model.

No need to confuse a network filter and a regular extension with multiple sockets. Externally, these devices look very similar to distinguish hard.

But ordinary extension cords Do not perform any functions of protection against voltage jumps and from interference. In this case, the extension cords can also have a switch with a light bulb than they are even more become similar to network filters. And at the price of extension cords, as a rule, cheaper than network filters, because there is no electronics that protects the computer from voltage jumps and from interference.

You need to know!

The network filter protects computer equipment from pulsed voltage and high-frequency interference jumps. Most often, it is through it that the computer is connected to the power grid. But no matter how high-quality network filter is, it cannot provide 100% protection against all the shortcomings of the household power supply.

With the task of 100% protection of computer equipment from problems with household electrical networks, only voltage stabilizer and some UPS models in Russian can be cope (reduction from uninterruptible power supply) and UPS in English.

Only for laptop owners

Laptops are in their own composition. And at the expense of these batteries, laptops also know how to smooth out voltage drops in the electrical network. It would seem that in this case there is no need to connect a laptop to an electrical network via a network filter.

No! Network filter is very useful device For laptops and their owners. The fact is that the batteries of laptops are quite capricious, and quickly fail if they influence them with them.

Especially the batteries of laptops do not like when they are left connected to the 220V electrical network when the laptop is turned off.

So, turning off the laptop, the laptop charger must be disconnected from the 220V electrical outlet. And strictly B. obligatoryif there is no desire to get for a very short time rechargeable battery laptop.

But after all, "lazy" (in the literal and figurative sense) insert and pull the plug charger Laptop out of the outlet every time it is turned on or off. Here, a network filter comes to the rescue. Turn off the laptop, and then turn off the power filter with a slight press of the button (keys) of its disconnection. And before turning on the laptop, you can also easily turn on the network filter by pressing the appropriate key.

Of course, instead of a network filter, laptop owners can use conventional extension cords with a switch. It's cheaper. But not so much to neglect the network filter capabilities to smooth out the interference and voltage drops on the 220V network.

P.S. French scientist 18 in. Jean Leron D'Alumber: " Work, work - and the understanding will come later. "So you can say about computer literacy:

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The norm was the connection of computers, if not through the UPS (uninterruptible power supply), then at least through a network filter (in use the filter socket). Usually it is made in the form of an extension agent (in the photo at the beginning of this article, it is shown just a network filter for 3 outlets) However, for which it is intended and how people actually do not understand in electronics.

We will describe in detail, but not much deepening, especially in special terms about the appointment and principle of the operation of this device. We will also try to answer some of the most frequently arising questions, and we will try to tell how to choose the right network filter for your technique.

Standardly, in the electrical network there should be 220 volts with a frequency of 50 hertz, however, it never happens in practice. The fact is that the instruments connected to the network have different characteristics, and as a result of their turn on and off, the current parameters in the network are constantly changing.

The situation is all familiar when there is a welding connected from a neighbor, the light bulbs begin to flare up brighter in the apartment, then almost goes out. The voltage can significantly increase or decrease, the frequency and shape of the envelope varies. A situation is possible when due to the accident (overwear of the wires with different phases), the lightning strike or incorrect electrical action, the voltage jump will be significant, several times higher than the nominal value.

Also, there are interference with frequent more than 50 hertz. For example, sparkling contacts offer high-frequency interference (crackle in columns when pulling the fork of a table lamp from the socket is caused by them).

All this not only affects proper work Electronics, but also can lead to its failure. Of course, almost all household devices are equipped with overload protection, but most often it is only fuses that are triggered with significant overload, and then with some delay.

The network filter saves from all these troubles. It cuts off all the venge with a frequency different from the nominal, extinguishes the jumps and adjusts the voltage fed to the instruments connected after it. It is necessary to use it not only for a computer, but also for all complex household appliances.

How does a network filter

As mentioned above, the tasks at the network filter are three:

• Cut off all currents with a frequency above 50 Hz;
• Do the same with currents with a frequency below this value;
• Exclude voltage increases above 220 volts.

For their execution, three types of radio components are used:

• Capacitor, perfectly conductive high frequencies, but not transmitting low frequencies;
• inductor (choke), on the contrary, passing a permanent current, but is a resistance for AC;
• varistor (special semiconductor device), he has an interesting characteristic - to a certain voltage value, resistance is large, and when this threshold is exceeded, it drops sharply.

These elements are connected as follows:

• Capacitors - parallel to the load (the device connected to our filter). When high frequencies appear, they pass through them, but not through the load.
• The inductor coil is connected sequentially with the load, and does not allow high frequencies through it.

Several connected nodes connected to each other from capacitors and coils (LC contours) with correctly selected rates, improve the quality of filtering (selectivity).

• The varistor is connected, as well as a capacitor parallel to the load. With raising voltage, the current goes through it, and not through the load (the effect of the shunt).

In addition to these parts, the filter usually includes even additional radio elements, providing its better work, functionality, and excluding unwanted effects. For example, with a sharp disconnection from the network, the condenser large tank Itself can become a source of high voltage and high-frequency interference due to a sharp discharge (clicking when it is turned off, many audio systems are called precisely this process). Therefore, in parallel, it includes a resistor (resistance), which extinguishes the outstanding energy.

Recommending the appointment and device of filters, will answer the most frequently arising questions.

What other electrical appliances are preferably connected through the filter

The answer to this question is simple - almost all complex (it does not include light bulbs and electric heaters). Of course, most modern electronics feed on pulsed power supplies, which are less critical to high voltages and interference, but the excessive protection stage never hurts.

For sound-reproducing systems, the absence of frequency interference will improve their quality of work. You should also not forget that the network filter works in the opposite direction.

If the tips arise in the device itself, then it does not give them to penetrate the network. This feature additionally protects your information from unauthorized use. There are hidden access technologies that read data from devices based on power cable.

Network filter on the telephone line

In addition, the reason for the damage to the electronics can be non-standard characteristics of the supply network, interference and high voltage can penetrate through other connected lines: telephone, Ethernet, cable. Therefore, modern protective devices, besides ordinary power, additionally there is a socket telephone with a filter and connectors of other formats. What is also a good defense.

The principle of occurrence and suppressing unwanted impacts in these systems is almost the same, except that frequencies and voltages differ in systems. If there are no such additional connectors in your filter, you can purchase a protective device separately.

Does the filter need after the UPS

There is often such a situation - in the output connector, the UPS connected a filter to several sockets, and it is already all the periphery. This is unnecessary, since the "uninterrupter" has a built-in filter (there will be a sufficient simple extension agent into several sockets).

A little distract from the topic. The UPS is calculated that with the sudden disconnection of electricity, we could save necessary information (For old cars, it is correct to turn them off, turning the hard drive). For periphery, it is not important.

Connecting the entire periphery after the "uninterrupted", we will take the battery charge on her job, and reduce the time of the computer. It makes sense to connect to the UPS only a router or a modem if we store the data in the "cloud". The remaining peripheral equipment connects with the network through the filter.

What is the master socket

We will analyze the question - a network filter with a master socket, how it works, and whether this feature is needed. it additional option Network filters having several outlets. In such devices, one connector is assigned to the eldest (MASTER), and all the others are anximary (Slave). Usually, the system unit is connected to the senior connector, and in the other other periphery: monitor, modem, printer, audio system, etc.

The filter electronics tracks whether there is electricity consumption over the Master connector, if it is not, then all the others are disconnected. This is very useful featureallowing good to save electricity.

It is also convenient to use this filter to use such a filter - there is no need to press the power keys of all devices upon completion of the work. Fully disconnected devices do not consume energy at all, in contrast to waiting mode and more fireproof.

Such a filter is convenient not only for a computer. In addition to him, there may be several more systems in the house, the work of which is tied to the main device, for example: TV, DVD or Blue-Ray player, satellite receiver, home cinema.

Without TV, the rest are useless. True, after the voltage is served, many of the systems will be translated from the waiting mode to the workman, manually. But, in most cases, modern technique is easily associated with other channels and independently turns on.

Is it possible to collect a network filter yourself

If you are not bad, not even in radio engineering, but simply in electrical engineering, then make the simplest filter with your own hands will not be difficult. The scheme (and their full on the Internet) is not more difficult than for a reversing connection of a three-phase motor. We, by the way, led to one of them. Here is an option yet.

All its components are not difficult to buy in specialized stores. Installation can be made even "canopy", without pCB (Do not forget about reliable fixation of all parts and requirements of electrical safety).

Details for such a filter are not necessary to buy - capacitors and resistors can be dropped from the failed equipment. The throttle is more difficult to find, but you can hide yourself. The problem may occur only with a varistor, though the price of this device is small semiconductor device.

When using parts from the written technology, pay attention to the working voltage of the capacitors - it should be at least 400 volts (better more, despite the fact that we have 220 on the network). This will ensure reliable operation at voltage jumps.

Important: Cannot be used for alternating current filter, polarized electrolytic capacitors. Please note that the polarity of the connection ("-" or "+") will not be indicated on the instrument housing

How to choose a network filter for home appliances

The fact that the network filter is needed, we have already explained. But how to choose specific modelwhich reliably protects your electronics, and at the same time, will not burden the wallet? The video below should help you.

Instructions, how to pick up will be as follows:

• Determine the total power of those devices that are going to connect through it. And we take a peak load, and not in standby mode (for example, laser printer During printing can take up to 3 kW). Add a 20-25% stock to the resulting digital.
• It is also worth considering that power consumed may increase if we are going to handle our system upgrade or purchase additional devices. Select the filter that allows this power of the plug-in (if the current is specified, then we simply multiply by 220, w \u003d i * u and get power in wats).
• We define what additional functions we need, and which excess and select the model with such possibilities. You should not buy, for example, a model with a telephone socket protection, if the computer is connected to the Internet via Xpon (fiber optic cable).
• We choose a model that suits the price. Moreover, it is even better to navigate the brand not even fame, but on customer feedback on reputable sites (Ayrekomned, Ozzovik), but not on the store page (there are positive estimates may be paid).

Tip: Do not choose cheap network filters. Most often it is a fake, and from the protective elements in them there are, at best, only capacitors. The suspicion must be called low weight and dimensions. They work only as extension cords. The photo above shows such an instance in disassembled form.

That's all that we could tell you about network filters. If you understand that a network filter on 5 sockets is not the only characteristic of the device, then we did not work in vain.

These values \u200b\u200bare very secondary, and it is much more important to know the main technical parameters. We will be glad if this article helped you understand the principle of operation of this device and its purpose, answered the most frequently arising questions.