The fall of the support in the area of ​​the cross section. The Great Encyclopedia of Oil and Gas

Opіr provіdnik to lay down in yogo rozmіrіv that form, as well as in the material, z kakogo provіdnіk preparations.

For a uniform line conductor, opir R is directly proportional to the cross section ℓ and is wrapped in proportion to the area of ​​the cross section S:

de ρ - electrical opir, which characterizes the material of the conductor.

§ 13.4 Parallel and subsequent meetings of conductors

At last meeting of conductors

a ) the strength of the struma is the same for us in the lands of the lansyug, tobto.

b.

c) the fire of the lancer is more expensive than the sum of the supports of the okremih conductors:

or

(13.23)

At parallel connection of conductors three laws follow:

a) the total strength of the struma in lances is equal to the sum of the strum forces in the other conductors:

b) the voltage on all parallel plots of the lancer are the same:

c) the value wrapped up to the tan support of the lancet, which is equal to the sum of the values ​​wrapped up to the support of the skin conductor okremo:

or

(13.24)

§ 13.5 Electrical lanyards. Kirchhoff's rules

In case of violation of the task, order according to Ohm's law, manually victorious two rules of Kirchhoff. When folded folding electric coils at certain points converge wire conductors. Such points are called knots.

The first rule of Kirchhoff is grounded on the upcoming mirkuvannyah. Strumi, to enter at the tsey vuzol, bring a charge from the new one. Strumi, which squeal from the knot, take the charge. The charge at the node cannot be accumulated, so the value of the charge that enters the node in a given hour is exactly equal to the value of the charge that is charged from the node, for the same hour. Strumi, which enter at the same node, are considered positive, strumi, like from a node, are entered by negative ones.

Zgidno Kirchhoff's first rule , the algebraic sum of the forces of the strums at the conductors, which rise at the nodes, up to zero.

(13.25)

I 1 + I 2 + I 3 +….+ I n =0

I 1 + I 2 \u003d I 3 + I 4

I 1 + I 2 - I 3 - I 4 =0

Another rule of Kirchhoff: the algebraic sum of creating the support of the skin from the dilyanok of any closed contour of the galvanized lancet of the postial strum on the force of the strum on this dimension is more advanced to the sum of the algebra of EPC of the vdozh tsgo contour .

(13.26)

E then the rule is especially handy to stick in that fall, if the contour is drawn not by one, but by a sprat of a struma (Fig. 13.8).

When vikoristannі tsgogo rules directly strumіv and detour vibirayutsya enough. Strumi, which is to turn straight ahead around the contour, are considered positive, and those, which go against the straight line, are negative. Apparently positive, the EPC is quietly dzherel, like calling out a strum that runs straight around the circuit.

ε 2 –ε 1 =Ir 1 +Ir 2 +IR (13.27)

Side 1

Pytomy opir of the conductor should be deposited depending on the temperature, vice, material and other factors, after which, depending on the factors, deposit and opir of the conductor. The most practical value is the fallow pet support, and also, the support of the conductor in the temperature. In vipadku tsya staleness is foldable.

Pytomy opir conductors are not constant, but fallow temperatures. For all metals, the opir zbіlshuєtsya zі zbіlshennyam temperature. At low temperatures, the fallow of the pet is supported by the temperature following a linear law. For skin metal, the temperature coefficient of support a is used, which determines the change of the pet support of the conductor, up to one ohm when the temperature rises on the HS.

Pytomy opir conductors lie at the boundary between 10 - 6 to 10 - 2 ohm-cm, and technical dielectrics at 109 to 1020 ohm-cm. Cі between the singing world of the mind, but approximately reflect the manifestations that have become established in technology.

Pithomium opir conductor є opir drotu dozhinoy I m і transverse area of ​​1 mm2 at a temperature of 20 C.

Pythomium opir conductors and non-providers lie down in temperature.

Pythomium opir conductors of the first kind should be deposited at temperature. As a rule, due to the increase in temperature, it moves. Vignatok to make graphite and vugillya.

The lesser nursery of the opir conductor, the lesser amount of heat (moreover, the strum) is seen by the new one. When there is a superconductivity, if the petty opir becomes unstoppable and small, the conductor does not see a little bit of heat during the passage of the struma. So, as with all the energy of the stream, it doesn’t show up anywhere, then once the closed superconductor wakes up; podtrimuєtsya at the new one is not known for a long time without spending energy calling.

Changing the support of the conductor under the influence of the wind, which is stretched or squeezed, is called a tensoresistive effect. Vin is characterized by strain-sensitivity, which establishes a connection between a visible changeable support and a visible deformation.

Here r is the nursery of the opir of the explorer, other signs of decryption in the forward task.

Vіd chogo to lay kennel opir conductor.

Yakbi the value of the supported support of the conductor p did not depend on the temperature, the difference between the allowable thickness of the struma / 1Dp and the allowable displacement of the temperature of the conductor at short flicker would be good to forgive. In fact, the pitome of the opir r changes with the heating of the conductor, and the spivvіdnennja mizh schіlnіstyu strumu and perevischennyami temperatures go folded.

In order to increase the value of the pet, the support of the conductors is to zastosovuyt alloys of decile metals. It has been established that only alloys with an unordered structure can increase the value of the support and the value of the temperature coefficient of the support is small. Alloys with an unordered structure are called such, in the crystal solution there are no correct drawing of metal atoms, which form metal. Qi alloys form a group conductor materials with a large pet support and small values ​​​​of the temperature coefficient of the pet support. All the listed groups of conductors have high plasticity, which allows you to trim darts with a diameter of up to 001 mm and lines with a torso of 005 - 01 mm.

Side 2

The temperature deposit of the support of metal conductors is widely vicorated by the technician until the thermometer support is assembled. By placing support 7.0 in the furnace spiral and vimiryuyuchi її opіr Rt, it is possible (15.10) to determine the temperature of the furnace. On the other hand, the temperature stagnation slowly pours into the work of precise electrical appliances, changing the rest of the rest while changing the best minds.

According to the electronic theory, the opir of metal conductors of the electrical struma is blamed on the fact that the wearer of the struma - electronic conductivity, in their own Russia, is struck by the ions of the crystal gates. When the electrons are collapsing, they transfer to the ions a part of their energy, given by them during a free run in electric field. Vidminnist at the support various metals explained in terms of the value of the average free run of electrons and the number of free electrons in a single volume of metal.

Due to temperature changes, the main metal conductors are increased, and due to decreases, they are changed.

When changing the temperature, the opir of metal conductors changes (for the highest temperatures) according to the law R Ro (1 - f - 0 004&), de / 4 - opir at 0 С і & - temperature per Celsius. Tsey law is fair for the majority of pure metals. Conductor, which is operated at 0 C, cools down to 10 ohms, evenly heats up from 8j 20 to 02200 with a draw of 10 min. The same way, the strum under the pressure in the 120th century.

According to the electronic theory, the opir of metal conductors of the electric struma is blamed on the fact that the wearer of the struma - electronic conductivity in their own Russia recognizes the zіtknennia with the ions of the crystal lattice. When the electrons collapse, they transfer to the ions a part of their energy, given by them during a free run in the electric field. The difference in the support of various metals is explained by the difference in the value of the average free range of electrons and the number of free electrons in one unit of metal.

Vіd chogo to deposit opіr metal conductor.

When changing the temperature, the opir of metal conductors changes (at the highest temperatures) according to the law R RQ (l 00040), de D0 - opir at 0 C and 9 - temperature over Celsius. Tsey law is fair for the majority of pure metals. Conductor, which is operated at 0 C 100m, evenly heated from 0g 20 to 02200 with a stretch of 10 min.

With an increase in temperature, the opir of metal conductors will increase, and with a change, it will change.

When changing the temperature, the opir of metal conductors changes (at the highest temperatures) according to the law R - R0 (l - f 00046), de Ro - opir at GC і 6 - temperature over Celsius. Tsey law is fair for the majority of pure metals. Conductor, which is used at 0 С 10 Ohm, evenly heats up in 8i 20 to 62200Е with a stretch of 10 min. At the same time, a strum was going to him with a voltage of 120 V.

Dosledi show that the opir of metal conductors should be deposited in the form of a conductor and the material from which the conductor was prepared.

Like a manifestation, to build up the support of the metal conductor to the zbіlshennya.

AR and CR are characterized by the spivvіdnennym supports of metal conductors between the frame and the cathode, from one side, and between the frame and the anode, from the other side. If you choose an opir conductor that connects the frame with the anode, so that the skin value of AR and CR was between 0 8 - 1 5 (with a pressure on the compressor of 2 3 c), then the frame cannot take part in the electrochemical process gas-like water and sour are not seen on the surface. As well as the back of the frame with the anode behind the auxiliary conductor of a small support, the potential of the frame can destroy the flooring in the anode side, so that on top of the frame it will be included in the electrochemical work, like an anode with seeing sour in the cathode, it will open up and become clouded with sour water.

The method of support is grounded on the appearance of changing the support of the metal conductor in the light of temperature.

The ground support of the grounding outbuilding is built up from the supports of metal conductors, grounding slopes and that support, which the earth rises. electric struma. Active Opir There are few metal conductors and grounding descents of the flooring in a porous support with a rosette, which, as a rule, they do not need. Therefore, the term opir of a grounding outbuilding means nothing else, like an opir, which is to repair the passage of an electric struma earth, which is a metal conductor. At the process of sinking a struma into the ground, the grounding machine is pumped up according to the distance to the distant points of the earth, the potential, which is equal to the magnitude of the voltage drop, as if it were called by the struma that it should pass near the earth.