Zapobіzhniki, scho samovіdnovlyuyuyutsya. Myth and reality

In the comments, before my last article, I was reproached more than once for those who, having not guessed the way to defend the victories of the defender, to self-identify. In order to correct this injustice, I would like to just add to the article the supplementary scheme of defense and a short explanation to it. However, vyrivishiv, that the topic is zapobіzhnіv, that they are self-sufficient, meritorious for a good publication. On the right, the fact that their name does not reflect the essence of speeches, but digging in datasheets and sorting out the principles of work when such "elementary" components are loaded, like a lover, often starts right after the first batch of boards started to fail. Good, it's not serial. Otzhe, under the cut, a check is made on you for a sample, what kind of a beast is this PolySwitch, The original name, to the point of speech, more briefly reflects the essence of the accessory, and understand why you should eat it, like in some situations you can sense vikoristovuvati yoga.

Physics of a warm body.

PolySwitch, ce PPTC(Polymeric Positive Temperature Coefficient) - an attachment that can support a positive temperature coefficient. To tell the truth, there are more rich rice with a posistor, or a more metal thermal protector, a lower one with a fusible one, with which it sounds associated not in the rest of the black zavdyaki zusilli marketologists.
All the cunning is in the materials of what our zapobіzhnik of preparations - wine is a matrix of the polymer, so as not to carry out a strum mixed with technical coal. In the cold camp, the polymer of crystallizations, and the expanse between the crystals is filled with particles of coal, which make up the impersonal lances, which are carried out.

As if, through the zapobіzhnik, a too great strum began to flow, the wines began to heat up, and at that hour the polymer passed into an amorphous state, growing larger at the expansions. Through the thickening of the coals, the lances begin to rise, calling out the growth of the support, and the protector heats up even more. Zreshtoy opir zabіzhnik zbіlshuєtsya nastіlki, scho vіn vіn vіn commemoratively encircle the strum, which flows, protecting with such a rank the zvnіshnіy lantsyug. As soon as the device is reached, the process of crystallization begins and the guardian becomes a miraculous guide again.
As if looking at the temperature, the support can be seen from the stepping baby

On the curve, a sprig of points characteristic of robots is shown. Our protector is a supervising guide, as long as the temperature is in the operating range of Point1< T

Ideal spherical tip in vacuum.

It's time to move from theory to practice. Let’s choose a simple scheme for the protection of our valuable outbuilding, the flooring is simple, which is depicted behind GOST, it would look simply obscene.

What do you think, if in lancius with a rapt vinikne an unacceptable strum, what is the strum of spratsovuvannya moving? Opіr material, z kakogo prilad preparations, more grown. Tse led to an increase in the fall of the voltage on the new one, and that means tightness, which rises, even U * I. As a result, the temperature rises, so I need to bring it back up to ... The process of avalanche-like heating of the fixture with an one-hour increase in the support begins. As a result, the conductivity of the attachment drops by orders of magnitude and it is not possible to bring the struma of the lancet to a baggy change.
After that, how the attachment achieves this opir is renewed. In a deaky hour, on the vіdmіnu vіd zapobіzhnik іz fusible insert, our Ideal Zapobіzhnik is ready to work again!
What is ideal? Let's use our modest knowledge of physics by hand, let's try to get into it.

It was smooth on paper, they forgot about Yari.

Maybe, the head problem is near the hour. Such a substance took off for an hour, it’s very important to overcome it, even if you wanted to be rich… But let’s not talk about politics - closer to our polymers. As you sing-songly already guessed, I lead to the fact that the change of the crystal structure of the speech is a richly trival process, lowering the wires with electrons, for example, at the tunnel diode. Krym tsgogo, schob rozіti prilad to the required temperature, a deaky hour is needed. Through the war, if the strum through the zapobіzhnik rapt outweigh the boundary value, this obezhennya will not be mittevo. With streams close to the threshold, the whole process can take a few seconds, with close streams up to the maximum allowable for the attachment, a fraction of a second. As a result, in an hour of spratsyuvannya such zahistu foldable electronic devices managed to get out of tune, maybe more than a dozen times. On confirmation of the flooding, a typical fallow schedule for the hour of spration (vertically) in the stream (horizontally), which called for the spratsyuvannya, for the hypothetical PTVC fit.

To pay respect, which was put on the schedule for the equalization of two fallows, taken for different temperatures in the middle of the earth. I am more aware that the temperature of the material, and not the strum that flows through it, is the primary cause of the crystal structure. Tse means that of the other equals, in order to build up an adaptation to the metamorphosis at a lower temperature, it is necessary to spend more energy at lower temperatures, also, and the whole process at the first fall will take more than an hour. As a last resort, we take into account the staleness of such the most important parameters of the device, as the maximum guarantee of the normal operation of the strum and the guaranty of the strum of the spratsovuvannya according to the temperature of the superfluous medium.

First, draw a graph below to guess about the main technical characteristics of this class of devices.

• The maximum operating voltage Vmax - is the maximum allowable voltage, so that you can measure the attachment without breaking for a nominal stream.
• The maximum allowable strum Imax is the maximum strum that can be used without rubbing.
• Nominal working squirt Ihold - This is the maximum strum that can be carried out without robotic assistance, that is. without rozmikannya lansyug navantazhennya.
• The minimum strum spratsovuvannya Itrip - tse minimum strum through the attachment, which leads to the transition from a wired station to a non-conductive one, tobto. until spratsovuvannya.
• Cob opir Rmin, Rmax - opir fit to the first spratsovuvannya (with otrimanny vіd virobnik).

At the bottom of the graph there is a working area of ​​the fitting. What will happen in the middle part of the deposit, judging by the mustache, in view of the mutual rotting of the stars in the sky, but after visiting the upper part of the graph, the device will break at the road (trip), like a metamorphosis of the yogic crystal structure and as a legacy of spratsovvanya Below is a table with data on real fittings. Retail in the stream spratsovuvannya in fallow land in vіd temperature vrazhє!

In this way, in outbuildings, which are used for work in a wide temperature range, PPTC should be installed with care. If you think that the problems of our candidate for the title of the Ideal Zapobіzhnik are over, then you will have mercy. There is one more weakness, powerful to people. If I become stressed, caused by overheating, I need to return to normal. However, the physics of a hot body is already similar to soft physics. Like a man after a stroke, our zapobіzhnik will no longer become so much! For the sake of controversy, I’ll bring a rough schedule for the rehabilitation process after stress, calling for the transfer of the strum, which, better than the English word, was called the Trip Event. And how can you not be afraid of our Rosspozhivnaglyadu?

It can be seen from the graph that the process of renewal can take place, but we won’t do it again. From the skin vapadkom spratsovuvannya zakhistu normal opir of our prilad becomes more and more and more. After a few dozen cycles, the prilad vzagali spent the building of the building of the deposit on the new function with a proper rank. That's why it's not varto to beat them in vipadkas, if the overwhelm is possible with high periodicity.
Perhaps, on which varto bullo b and finish, and arreshti proceed before discussing the areas of design and circuit solutions, ale varto discuss the nuances, for which we marvel at the main characteristics of the widely widened series of our hero of the day.

When choosing an element, which you will win in the project, respect the maximum allowable working strum. Yakshcho high ymovіrnіst yogo relocation, varto turn to an alternative form of zakhist, or surround yogo for help with another accessory. Well, for example, a dart resistor.
Another important parameter is the maximum operating voltage. It was understood that if the attachment is switched to normal mode, the voltage on these contacts is even small, but after switching to the off mode, it can be sharply increased. Not long ago, this parameter was too small and surrounded by tens of volts, which did not make it possible to achieve such victories in high-voltage lances, let's say for the outrageousness of life blocks.
In the rest of the hour, the situation brightened up and a series appeared, invested in doing a lot of work, but to gain respect, that the stench may be small working jets.

We cross the vozha and the trembling doe.

Judging by the fact that the diversity of the attachments in PolySwitch promotes the market, it is possible to use them in the attachments that you are expanding, but in a few cases it is necessary, even before the choice of a specific attachment and the method of yogo selection, it is necessary to achieve great success.
Before the speech, if the circuitry, the direct replacement of fuses on PolySwitch is good only in the simplest situations.
For example: for vbudovuvannya in battery vіdsіki or for zahistu obladnannya (electric motors, activators, mounting blocks) and electrical wiring in car accessories. Tobto. annexes, yakі do not go out of tune mittevo under the hour of changeover. Specially for this, a wide class of these attachments have a view of jumpers with axial leads and wind disks for batteries.

For most of the PolySwitch switches, you can combine the varto with more swede-coded outbuildings. Such a pidhіd allows compensating richly for their shortcomings, and as a result, successfully zastosovat for the invasion of peripheral devices in computers. At telecommunications, for the protection of automatic telephone exchanges, crosses, fringing of the air in the splashes of the struma, causing the consumption of line voltages and sparkles. And also with robots with transformers, signalizations, guchnomovtsy, control and monitoring equipment, satellite televisions, and in other ways.

The axis is a simple butt to the USB port.

As a complex pilot, we can look at a hypothetical scheme of a comprehensively vicious task of stimulating a super-protected light-diode driver with a life-changing voltage of 220V.

At the first stage, there is a guard, which is self-sufficient, of blockages at the connection with a rattling resistor and a varistor. The varistor protects against sharp fluctuations in the voltage, and the resistor surrounds the stream, which flows into the lance. Without this resistor, at the moment the pulsed dzherel is turned on, life through the guard can flow an unacceptably great impulse to the stream, charging the charge of the input capacities. The other step guards the guard against the wrong polarity shifting, or for the mild connection, the life of life from a too great strain. If so, at the time of an emergency, the streamer takes on a TVS diode, and the PolySwitch surrounds the tension, which flows through it, preventing the thermal breakdown. Before speech, the connection of the flooring is suggested in the course of the development of circuitry and the flooring is widened, which gave rise to a new class of devices - PolyZen. Far away, the hybrid vuzha that quivering deer.

Well, at the end of the day, our protector, which is self-sustaining, serves to intimidate a short flicker, and so on the way out of the operating mode of the light, or the drivers will result in overheating, or a malfunction.
The scheme also has elements of protection from statics, but it’s not the topic of statistics anymore.

Perederzheny means ozbroєny.

In parting, let's briefly pіdіb'єmo pіdbags:

• Polyswitch is not a fusible successor.
• Zastosovuyuchi Polyswitch is necessary to deal with those, shchob strum, which through a new one to pass through in a random situation, without exceeding the tolerances. Necessary zastosuvannya obzhuvachіv struma. In the case of other intermediary conditions, there may be such elements as connecting rods (vehicle wiring) or internal batteries / accumulators. In such cases, the simplest scheme of switching on until the opening of the lancet is possible.
• Polyswitch is more of an inertial tool, it is not suitable for outrageous schemes that are sensitive to short shots. In these types of yoga it is necessary to zastosovuvat spilno with other elements of zahistu - zener diodes, suppressors, varistors, surge arresters, just so that you don’t need to enter the house, which surround the maximum strum at the lance.
• Zastosovuyuchi Polyswitch next step, so that the voltage on the new one did not exceed the allowable. A high voltage may appear after spratsyuvannya prilad, if yogo opіr zbіlshuєtsya.
• A trace of remembrance, that a lot of spratsovuvan prilad is rimmed. After skin application, the characteristics are improved. Vіn go for zakhistu lanziugіv yih perevantazhennya є every day business.
• Well, come on, don’t forget that the strum spratsovuvannya tsgogo prilada istotno lie down at the temperature of the right middle. Chim won't win, Tim will win mensha. It is also possible to apply insurance for operation in a wide temperature range, or periodically work in the zone of rising temperatures (a tight block of life or a lowering of the LF), you can bring it up to pardon.

P.S.

Specially in order not to show a little bit of a koristuvach

The principle of a robotic superb fusible protector is based on the thermal power of an electric jet. A thin copper wire is placed near the ceramic or glass flask, which burns out, if the strum, which passes through it, quickly turns over the deak, zazdalegіd is appointed, significant. This is why it is necessary to replace such a guardian with a new one.

Defenders who are self-reliant, on the vіdmіnu vіd vіdmіnіh fusible zapobіzhnіv, can spratsovuvati and vіdnovlyuvatis bagatorazovo. Such zapobіzhniki, scho samovidnovlyuyutsya, often vikoristovuyutsya in computers and game consoles for the protection of USB and HDMI ports, as well as for the protection of batteries in portable technology.

The essence of the offensive. A non-conductive crystalline polymer should be introduced to the new fine particles of technical carbon, as a result of subdivision of the polymer so that it is possible to conduct an electric jet. Stream-conducting electrodes are deposited on a thin sheet of plastic, as they spread energy over the entire area of ​​the element. A visnovka is attached to the electric wires, which serve as the inclusion of the element in the electric lance.

The peculiarity of such a conductive plasticity is the high non-linearity of the positive temperature coefficient of support (PTC), which serves for the protection of the lancer. In addition, as soon as the strum is overwhelmed, the element will heat up, and the plastic, which is to be carried out, will sharply increase, and it will lead to the opening of the electric lance, where the element is included.

To bring the temperature threshold up to the transformation of the crystalline structure of the polymer into an amorphous one, and the lances of technical carbon, like passing through the stream, are now collapsing - the opir of the element is sharply growing.

Let's take a look at the main characteristics of zapobіzhnikіv, scho self-sustaining.

1. The maximum working voltage is the voltage, as you can see the guard without ruining, for washing the nominal stream through it. Sound the value to lie in the range of 6 to 600 volts.

2. The maximum strum, which does not lead to spratsovuvannya, the nominal strum of the defender, which is self-sustaining. Sound from 50mA to 40A.

3. The minimum strum of spratsovuvannya is the meaning of a strum, for which a conductor will turn into a non-conductor, tobto. the meaning of the struma, in which the lanceg is roaring.

4. Maximum and minimum opir. Opir at the work station. It is necessary to select the element from the lowest value of the parameter from the available ones, so that the new one does not take on the burden.

5. Operating temperature (sound from -400 to +850 C).

6. The temperature of spratsovuvannya, or else - the temperature of the "pinching" (sound out +1250 C for better).

7. The maximum allowable strum is the maximum at rated voltage, as you can see the element without rubbing. If this strum will be moving, the guard will simply burn. Sound the value in tens of amperes.

8. Shvidk_st spratsovuvannya. The hour of heating up to the temperature of the spratsovuvannya to become a fraction of a second, and to lie down in the struma overwhelmed by the temperature of the necessary medium. In the documentation for a specific model, qi parameters are assigned.

Zapobіzhniki, scho samoіdnovlyuyutsya, vypuskayutsya both in cases for installation in the open, and in SMD cases. At a glance, such zabіzhniki guess varistors or SMD resistors, and widely zastosovuyutsya in the lancets of the various electrical outbuildings.

Zapobіzhnik, scho samoіdnovlyuєє in other words can be called champion. Zapobіzhnik is a polymer resistor that provides a positive temperature coefficient of support. Vykoristovuetsya for zakhistu vіd revantazhennya lanzugіv along the strum or one-hour zakhistu for tension and strum at the borders vіd 3А up to 100Аі vіd 6V to 250V.

Defenders, who are self-innovated, revitalize in traditional designs with fusible inserts and feasibility self-improvement of conductive facilities after spratsovuvannya that completion infusion spontaneously.

Building of automatic notification of zapobіzhnikov soon an hour that vitrati for maintenance and repair of electrical installations.

The growth of the struma, which should pass, or the temperature of the superfluous middle, which exceeds the nominal value, leads to an increase in the support of the guard in the boundaries vіd 0.0026Ω up to 60Ω, melting of crystalline streak-carrying particles and rozmikannya of the lancelet by the year. Shvidkist spratsovuvannya deposit in a specific series and three in the boundaries vіd 0.15 to 40.00 s.

After the fall of the lansyug, the temperature of the zapobіzhnik decreases, influencing the cob parameters. Self-advancement comes into play. Varto designate what kіlkіst spratsovuvan obmezhena. After dermal treatment, the indications become worse.

Choice of a viable guardian it is necessary to take into account the following characteristics: the type of collar (with radial, axial windings, or for surface mounting in SMD vikonn), the maximum strum, which does not lead to spratsovuvannya (recommended to choose these values, which will change the strum of the lance) the temperature of the working medium, which is poured into the spratsovuvannya strum.

Zastosovuyutsya represented zapobіzhniki in computer, telecommunications and cross-country equipment, medical equipment, batteries, automobiles and other electrical equipment.

Detailed characteristics the main parameters of the guards that are self-sustaining appear on the tables. Decryption of marking, staleness of the struma, which should not be brought to spratsovuvannya, depending on the temperature of the necessary medium, rosemary, recommendations for installation and soldering pointed below.

The guarantee of the work of the zapobіzhnikіv, which are supplied by our enterprise, is self-sustaining, become 2 rocky. Tse podkrіplyuєtsya with reliable documents z yakosti.

Residual price for the deposit, which is self-sustaining, deposited according to the quantity, terms of delivery, harvester, margins and payment form.

V. Okhrimenko

The article shows the characteristics of the successors of the Littelfuse company, which are self-sustaining.

Entry

The traditional way to protect yourself from overwanting along the stream is to place fusible or zapobіzhniks who are self-reliant.

The Littelfuse company is a leading manufacturer of passive electronic components for "protection" of various types of electrical appliances. One of the most important directives is the susceptibility of the defenders, the main recognition of which is the protection of the superfluous strum in the event of an emergency situation in the system. Crimea of ​​classic fusible zapobіzhnikіv, the company in Denmark is issuing and sov. zapobіzhniki, scho samoіdnovlyuyuyutsya (polymeric positive temperature coefficient devices) [ - ].

Those who are self-sustaining are, in fact, polymer thermistors with a positive temperature coefficient (PTC). In some add-ons, PTC polymeric protectors (nadali polymeric protectors) can be successfully beaten to replace the standard fusible protectors (fuse).

I Floodkі Ta Polіmernі Scriptures for Zahista Prolfish Vіd Turning on Strucks for Vinjnenni Avarini Modev at Systems, Systems Systems, Zicninnya Loafinnya, Tu People Vikniknennya Daughty Ta Moisy Risika Uzagornownaya Electrichnaya Strap, and Horuzvynya Defectors Blocking Ta unfriendly naslіdkіv.

However, these types of zapobіzhnikіv are based on different technologies of production, and in general may have different unique characteristics, advantages and disadvantages. Understanding the features of technology and the principle of dії to help you find the right choice for a specific program with the improvement of the necessary numerical parameters. Perhaps, the main thing is that polymeric defenders recreate their characteristics (crime of extreme vipadkiv) after the application of di nvantage, tobto. after lowering equal to the struma that flows through. Prote renewal of characteristics is considered in full agreement, which, of course, should be protected for її zastosuvanni at a specific addendum. Traditional swimming trunks for the improvement of the practicality of the system require obov'azkoviy replacement after burnout.

Oskіlki polimernі zabіzhniki vіdnovlyuyuutsya automatically, їх zasosuvannya vpravdovuєєtsya in lancets, in some shifts along the strum traplyаєєєєєєєєєєєєєі often, and also, yakscho access to the place of installation їх difficulties. Such vipadkah quickly wait for a guarantee and service maintenance. However, for the residual choice of the type of contractor, it is necessary to insure all the performance characteristics of the outbuilding.

І polymeric and traditional swimming trunks react in essence to the heat that is seen during the passage of the struma. At the fusible protector, melting of the fusible insert (that is, shaving the lansyug) and, zreshtoyu, yogo ruinuvannya is melted. The self-healing strum is less common in the lance due to the total increase in the value of the first support, which is also observed in the first heating.

Forgiveness of the attachment of the polymeric protector and the principle of yogo di offensives. The polymeric protector is a compound that is made up of a non-conductive polymeric material (as a rule, polyethylene) and conductive fractions of graphite. The signs of the presence of graphite canals in a normal state are a polymeric protector and a conductor from a low damp support. When rozіgіvі vishche for the same temperature (so-called transition temperature), the molecules of the polymer take away the additional energy, and the cob crystal structure is transformed into an amorphous one, after which the graphite channels are destroyed, which leads to a sharp change in the conductivity and in the case of a transition. At low temperatures, the polymer crystallizes, graphite channels are restored, which lead to the return of the guardian's powers.

The characteristic of the switching is shown in fig. 1. However, it is not enough for the one who has a larger support for the renewal of the head of the post. The number of transitions from a wired state to a non-conductive one is practically unbounded, that is. for the presence of catastrophic factors in the term of the service of the polymeric protector of the environment.

The article shows the characteristics and features of polymeric protectors (Polyfuse, Resettable PTC), which are released by Littelfuse.

Characteristics

Opir polymeric zapobіzhnikіv as a minimum vdvіchі greater in pіvnyannі z fusible.

On vіdmіnu vіd vіd fusible zapobіzhnіv, polimernі not bezpechenuyut povnogo razryuv lancer. That is why at the "turned-on" station (that at the station of the high support) the polymeric guards are characterized by a strum coil. Rosemary strum coil can reach as many as hundreds of milliamps. Swimming zapobіzhniki pіd h spratsovuvannya povnistyu rozryvayut lansyug protіkannya struma.

When choosing a polymeric protector, take care to change the parameters of the operating temperature range, dimensions, and compliance with standards. For certain types of polymeric protectors Tab. 1, the deposition of the nominal stream of temperature was determined.

Table 1

Depth of nominal jet temperature for some types of polymeric protectors Littelfuse.

Type Dowkill temperature, °C -40 - 20 0 23 40 50 60 70 85 Nominal strum (I hold), A 250R120T 0.18 0.16 0.14 0.12 0.10 0.09 0.08 0.06 0.05 250S130 0.21 0.19 0.17 0.13 0.11 0.10 0.09 0.07 0.05 16R110B 1.60 1.43 1.27 1.10 1.00 0.92 0.75 0.67 0.57 1812L200-C 3.08 2.71 2.35 2.00 1.80 1.60 1.50 1.07 0.80 0805L100 1.35 1.25 1.10 1.00 0.82 0.74 0.65 0.55 0.42 0603L025 0.32 0.29 0.27 0.25 0.21 0.18 0.16 0.14 0.10

The speed of the reaction of polymeric zapobіzhniki hirsh, lower in fusible. The frequency characteristic of polymeric protectors is rich in what is similar to tієї, as the melting protectors of the Littelfuse Slo-Blo type can be. The hourly characteristic of the inclusion is the staleness of the hour "burned out" in the stream that flows through. Tse, vlasne, the hour is turned on as a function of the stream. Rice. 2, a schedule of fallow time was plotted for the time of reference for the size of the strum, which flows through, for polymeric shoots in the 0805L series.

The maximum admissible strum through a polymeric fuse is 10-100 A, however, for some types of fusible strums, the maximum strum can reach a value of 10 thousand. ampere.

The designation of some basic electrical characteristics of polymeric zapobіzhnikіv is rich in what they say about it, which vikoristovuyutsya for fusible [-]. At the same time, in connection with the peculiarities of the technology of documentation, which Littelfuse hopes, such electrical characteristics of polymeric devices are induced as the main ones.

Strumming I hold (hold current). In fact, the nominal strum of the defender. Strum morning - the maximum strum, which can flow through the guard, and which does not lead to the transition to a non-conductive camp at a given temperature of the excess wind (calculate 20 or 23 ° C).

Strum spratsovuvannya I trip (trip current) - the minimum strum, at which the polymeric protector passes from the non-conductive mill at a given temperature of the necessary wind.

Maximum strum I max (maximum fault current) - the maximum strum that can be used without shock at voltage V max .

Maximum voltage V max (maximum voltage device) - the maximum voltage, which can be used without damage during the passage of the maximum stream I max. Slid vrakhovuvaty as the nominal value of the operating voltage, and the possibility of viniknennia raznomanіtnyh impulsnyh overshkod (for example, in the system of electric vehicles). Littelfuse's polymeric heat sinks are approved for work at voltages up to 60 V. For melting, heat protections are approved for voltages of 1000 V and more.

Exhaust pressure P dmax (power dissipated) - tension that rises by the guard when moving to a non-conductive camp for a given temperature of an emergency (sound 20 or 23 ° C).

Minimum opir R min (minimum resistance of device in initial state). The minimum cob opir of the guard at the wire station before mounting on the board, in fact, before the first soldering.

Type R typ

The maximum opir after renewal R 1max (maximum resistance) - the maximum opir at a given temperature, dimmer after one year after renewal or after 20 s after soldering at a temperature of 260 °C.

Table 2	Parameters of SMD zabіzhniki 0805L
Type I hold, A I trip, A Vmax At Imax BUT P dmax , Tue Hour spratsovvannya Opir, Om Strum, A Hour, h Rmin R type R1max 0805L010 0.10 0.30 15 100 0.5 0.50 1.50 1.0 3.5 6.0 0805L020 0.20 0.50 9 8.00 0.02 0.65 2.0 3.5 0805L035 0.35 0.75 6 0.10 0.25 0.75 1.2 0805L050 0.50 1.00 0.15 0.5 0.85 0805L075 0.75 1.50 40 0.6 0.20 0.09 — 0.35 0805L100 1.0 1.95 0.30 0.06 0.21

At Tab. 2 guidance parameters of polymeric protectors in the 0805L series, Tab. 3 - parameters of the guards in the 30R series.

Table 3

Parameters of the guards in the 30R series.

Type I hold, A I trip, A Vmax At Imax BUT P dmax , Tue Spratsovvannya hour Opir, Om Strum, A Hour, h Rmin R1max 30R090 0.90 1.80 30 40 0.6 4.50 5.90 0.070 0.220 30R110 1.10 2.20 0.7 5.50 6.60 0.050 0.170 30R135 1.35 2.70 0.8 6.75 7.30 0.040 0.130 30R160 1.60 3.20 0.9 8.00 8.00 0.030 0.110 30R185 1.85 3.70 1.0 9.25 8.70 0.090 30R250 2.50 5.00 1.2 12.50 10.30 0.020 0.070 30R300 3.00 6.00 2.0 15.00 10.80 0.080 30R400 4.00 8.00 2.5 20.00 12.70 0.010 0.050 30R500 5.00 10.00 3.0 25.00 14.50 30R600 6.00 12.00 3.5 30.00 16.00 0.005 0.040 30R700 7.00 14.00 3.8 35.00 17.50 0.030 30R800 8.00 16.00 4.0 40.00 18.80 0.020 30R900 9.00 18.00 4.2 40.00 20.00

Visnovok

Polymeric guards (Polyfuse, Resettable PTC) are analogous to fusible guards and, interchangeably with them, are inertial attachments that need to be protected during the hour of choosing a guard for a specific report. The next step is to get used to the cold stream, which is leaking, and the voltage drop on the new one. In some cases, wind the back wires, for example, the electrical wiring of the transport facility or the internal battery support can close the strum to the permissible level of the windshield.

It is impossible to forget that with the introduction of a polymeric protector, its characteristics deteriorate after skin application, and the specific features of the operation of such devices (for example, quiet, often with a strum) are added to the real number of applications.

Strum spratsovuvannya significant world lie down in the temperature of the navkolishny middle. As a rule, applications for operation in a wide range of temperatures, the choice of polymeric defences, can potentially be brought to pardon requirements.

The range of working temperatures of polymeric devices is -40...85 °С. Rice. 3 shows graphs of the deposition of nominal parameters in terms of temperature for fusible and polymeric sources.

A permanent change in the overall dimensions of modern portable electronics causes a change in the dimensions of the vicor components. Polymer SMD-applications type 0402 and 0603 can be successfully installed in laptops, mobile phones and other smart gadgets.

At Tab. 1...3 the parameters of polymeric fittings, which are produced by the company Littelfuse, are shown, Fig. 4 - possible options for their choice.

More information about Littelfuse's polymer partners can be found at.

So, є such a cunning electronic component with a long-term name - a protector that is self-sufficient. What kind of "zvіr" is this and how it works? About tse and timetsya.

Everyone knows the ultimate fusible protector. The sovereignty of wines is simple and non-abyak. The principle of yoga robots is based on the thermal energy of the electric stream.

A thin copper wire is taken, which shows the power of the strum, it is placed near a glass or a ceramic flask, so that when spratsovvanny metal is not splattered in different sides. In the case of a short fading in the scheme, ale bida, the wine itself “dies” forever.

To replace a faulty fusible protector, it is necessary to open the hull of the building, and replace the protector that burns. Ale, don’t start such an operation manually, don’t start that one. Therefore, in such situations, the zapobіzhnik, who is self-sufficient, is even a logical replacement for the fusible zabіzhnik.

Zapobіzhniki, scho samovidnovlyuyutsya, actively vykoristovuyutsya in computers and game consoles for the protection of ports (for example, USB, HDMI), as well as batteries in portable technology.

Father, let's take a look at how the power of the defender, who is self-sufficient (we will shortly call yoga joint venture), as well as some basic parameters.

Zapobіzhnik, scho samoіdnovlyuєєєєєєєєєєєєєєєєєєєєєєє іѕ spetsіlії provіdny plastic. Tsey plastic speech is special. The wine is made up of a non-conductive crystalline polymer and introduced to the most important particles of technical carbon. Parts of technical carbon are scattered in the bonded polymer conduct an electric streak freely.

The plastic itself is molded into a thin sheet and a blast-conducting electrode is sawn on the flat. Behind the electrodes, you can spread the energy on the entire surface area. Before the electric wires, attach pelyustkovy or drotyany visnovkas, rahunoks of such joint ventures are connected to the electric lance.

The main feature of plasticity, which is to be carried out, is a high non-linear positive temperature coefficient of support ( tks). It seems simpler, plastic, to carry out, carry out a strum doti, until the temperature exceeds the singing threshold.

After which plastic opir, what to carry out, sharply increases, what to produce before the electric lance is opened. It is worth noting that when the temperature threshold is exceeded, the crystalline structure of the polymer is transformed into an amorphous one, and the lances of technical coal, like those passing through the stream, collapse. Tse to build up to a sharp increase in support.

Sounds like heating, how to bring the polymer to a phase change? The increase in temperature of the polymer depends on the fact that in emergency mode, through the protector, it self-innovates, starts the flow of the strum, which changes the nominal (to be working). At the same time, the temperature of the outside material increases. Tse own line to bring to the "spratsovuvannya" zapobіzhnik.

Parameters of zapobіzhnikіv, scho samoіdnovlyuyuyutsya.

In order to competently choose a guardian who is self-reliant, for a particular one I will need to know the basic parameters. Let's take a look.

Maximum operating voltage ( Vmax or Umax, V). Tension, like a building vitrimati without ruining the zapobіzhnik, which is self-sustaining, when passing through a new nominal struma. For example, for zakhistu USB port pіdіyde joint venture with a maximum operating voltage of 6 volts.

Nominal working strum chi strum utrimannya ( I HOLD or I h, A). Strum, which can pass through itself a zapobіzhnik, which is self-sufficient, without "spratsovuvannya".

Minimum spratsovuvannya strum ( I trip or I T, A). The minimum strum through the joint venture, at which point the transition from a wired state to a non-conductive one occurs. In other words, tse strum, in case of any zapobіzhnik, scho samovidnovlyuєє, "spratsovuє" - rozmikaє lansyug.

Minimum and maximum opir ( Rminі R1max, Ohms). Tse opir zapobіzhnik, scho samovidnovlyuєєє. Otherwise, you can say, what is the operation of the joint venture at the worker's station, what should be carried out. Parameter R min is the minimum opir of the joint venture, and R 1max is the opir of the defender after 1 year after the rest of the work. Offending parameters are specified for a specific temperature, for example 23 0 C. R min і R 1max sound more simply, for example, like this: R = 0.5 ... 1.17 (Ohm).

Indeed, this is an important parameter. The smaller the wine, the better, the fact that the zabіzhnik is turned on sequentially, slowing down the struma (before the adventurous). And, as you can see, there is tension on the support. For accessories, which live in autonomous living cells (accumulators, batteries), it is better to choose a joint venture with a small support at the working station.

Working temperature zapobіzhnika, scho self-sustaining, sound to lie in the interval vіd -40 0 C before +85 0 С. For such a temperature, the opir SP practically does not change and lie at the boundaries of R min - R max . The temperature of the “pinch”, or in another way, spratsovuvannya sound to become +125 0 С and more.

One more parameter. Maximum admissible strum ( Imax, A). This is the maximum strum of a short flicker, which is a visible indicator that is self-sustaining, without disruption at rated voltage (V max). How to strum through the joint venture to shift the value of I max , in viide z fret back (in fact - “burn out”). Select the value of this parameter to lie in the interval of tens of amperes (40 - 100 A).

Also, an important parameter is the speed of spratsovuvannya joint venture ( Max. Time to Trip). So, as it takes an hour to heat up, then the zapobіzhnik spratsovuє not mittevo, but after another hour. It is not enough to milk and to become a part of a second. An hour of spratsovuvannya to lie down in the stream of overwhelm and the temperature of the necessary medium. Such parameters, as the hour of application, are indicated in the documentation for a specific model of the defender, which is self-sustaining.

Self-adjusting guards are available both in standard enclosures for mounting in the opening (THT technology) and for surface mounting (SMT technology). JV for installation in the open ovn_ look like a varistor and a disk case, or a straight cut.



SP for surface mounting are similar to SMD resistors, but they can also have a different case (as a rule, they look like plates with stitched frills).



Defenders who are self-sufficient launch such firms as Bourns and Fuzetec.

An example of zastosuvannya.

The butt of zastosuvannya zapobіzhnik, scho samovidnovlyuєєє, may be vikoristannya yogo in the block of life, about yak rozpovidalos on the sides of the site.



The new defender, who is self-sufficient, wins together with the other elements of the defense. Spratsyuvannya zakhistu do not pull after yourself the irrevocable burnout of the zabіzhnik, and start to work out in the wake of the adoption of an inaccuracy, or a short flicker in the scheme of life.