Copper-nickel wires. Advantages and production technology

Aluminum conducts current and is one of the best conductors in existence. It is used to make conductive busbars, cable lugs and sleeves, cable for overhead power lines, self-supporting insulated wire (self-supporting insulated wire) and wires of smaller cross-section (for domestic or industrial needs), coaxial television cable.

Types of aluminum electrical cable Source ru.prom.st

Production technology

To obtain a superconductor, a conductive layer consisting of an alloy of nickel and copper is applied to a copper wire in a vacuum along its entire perimeter, with diffusion into the surface layer of the base wire. A protective layer of metal is applied to the outside. After which the resulting wire is annealed in a vacuum for 30 - 180 minutes at 850-950 o C. To create a copper-nickel wire, pure (99.99) copper and nickel are used.

The effect of increased conductivity is formed in an alloy layer consisting of two metals, which is a thin-walled conductive tube-interlayer. Thanks to the diffusion interaction of the metal layers adjacent to the interlayer tube on both sides, the surface is almost ideal.

The application of wire layers occurs in vacuum equipment to prevent oxidation of the conductive layer. Therefore, the length depends on the capabilities of the vacuum equipment.

Calculation of resistivity of copper-nickel wire

High electrical conductivity is found in copper and aluminum, as well as in gold and silver. In other metals, electrical conductivity is significantly lower.

Table of electrical resistivity of metals

Due to the fact that there are two types of electrical resistances -

In connection with the electromagnetic phenomena that arise in conductors when alternating current passes through them, two physical phenomena that are important for their electrical properties arise.

The last two phenomena make it ineffective to use conductors with a radius greater than the characteristic depth of penetration of electric current into the conductor. Effective conductor diameter (2RBhar): 50Hz -7 Ohm. Using microohmmeters, you can determine the quality of electrical contacts, the resistance of electrical busbars, windings of transformers, electric motors and generators, the presence of defects and foreign metal in ingots (for example, the resistance of a pure gold ingot is half that of a gold-plated tungsten ingot).

To calculate the length of the wire, its diameter and the required electrical resistance, it is necessary to know the resistivity of the conductors ρ.

In the international system of units, resistivity ρ is expressed by the formula:

It means: the electrical resistance of 1 meter of wire (in Ohms), with a cross-section of 1 mm 2, at a temperature of 20 degrees Celsius.

Advantages and disadvantages of copper wires

Copper is a ductile transition metal. It has a golden-pink color and is found in nature in the form of nuggets. It has been used by people since ancient times - an entire era was named in its honor.

The table shows the electrical resistivity of steel and other metals

Today, copper wires are often used in electronic devices. Their advantages include:

• High electrical conductivity (the metal ranks second in this indicator, second only to silver). Compared to aluminum, copper is 1.7 times more efficient: with an equal cross-section, a copper cable passes more current.
• Welding, soldering and tinning can be carried out without the use of additional materials.
• The wires have good elasticity and flexibility, they can be rolled and bent without much harm.

Copper is only slightly inferior to silver.
However, until recently, copper wires were inferior to aluminum due to several disadvantages:

• High density: at different sizes, copper wire will weigh more than aluminum;
• Price: aluminum is several times cheaper;
• Copper oxidizes in open air: however, this does not affect its operation and is easily eliminated.

Conductor resistivity table

The table shows that an iron wire with a length of 1 m and a cross-section of 1 mm 2 has a resistance of 0.13 Ohm. To get 1 Ohm of resistance you need to take 7.7 m of such wire. Silver has the lowest resistivity. 1 Ohm of resistance can be obtained by taking 62.5 m of silver wire with a cross section of 1 mm 2. Silver is the best conductor, but the cost of silver excludes the possibility of its mass use. After silver in the table comes copper: 1 m of copper wire with a cross section of 1 mm2 has a resistance of 0.0175 Ohm. To get a resistance of 1 ohm, you need to take 57 m of such wire.

Chemically pure copper, obtained by refining, has found widespread use in electrical engineering for the manufacture of wires, cables, windings of electrical machines and devices. Aluminum and iron are also widely used as conductors.

The conductor resistance can be determined by the formula:

where r is the conductor resistance in ohms; ρ – conductor resistivity; l – conductor length in m; S – conductor cross-section in mm2.

Example 1. Determine the resistance of 200 m of iron wire with a cross section of 5 mm 2.

Example 2. Calculate the resistance of 2 km of aluminum wire with a cross section of 2.5 mm 2.

From the resistance formula you can easily determine the length, resistivity and cross-section of the conductor.

Example 3. For a radio receiver, it is necessary to wind a 30 Ohm resistance from nickel wire with a cross section of 0.21 mm 2. Determine the required wire length.

Example 4. Determine the cross-section of 20 m of nichrome wire if its resistance is 25 Ohms.

Example 5. A wire with a cross section of 0.5 mm 2 and a length of 40 m has a resistance of 16 Ohms. Determine the wire material.

The material of the conductor characterizes its resistivity.

Based on the resistivity table, we find that lead has this resistance.

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It was stated above that the resistance of conductors depends on temperature. Let's do the following experiment. Let's wind several meters of thin metal wire in the form of a spiral and connect this spiral to the battery circuit. To measure current, we connect an ammeter to the circuit. When the coil is heated in the burner flame, you will notice that the ammeter readings will decrease. This shows that the resistance of a metal wire increases with heating.

For some metals, when heated by 100°, the resistance increases by 40–50%. There are alloys that change their resistance slightly with heating. Some special alloys show virtually no change in resistance when temperature changes. The resistance of metal conductors increases with increasing temperature, while the resistance of electrolytes (liquid conductors), coal and some solids, on the contrary, decreases.

The ability of metals to change their resistance with changes in temperature is used to construct resistance thermometers. This thermometer is a platinum wire wound on a mica frame. By placing a thermometer, for example, in a furnace and measuring the resistance of the platinum wire before and after heating, the temperature in the furnace can be determined.

If at temperature t the resistance of the conductor is equal to r, and at temperature t is equal to rt, then the temperature coefficient of resistance

Note. Calculation using this formula can only be done in a certain temperature range (up to approximately 200°C).

We present the values ​​of the temperature coefficient of resistance α for some metals (Table 2).

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Advantages of nickel and nickel alloys Price of nickel alloys Density, concentration and resistance of nickel wire General information about nickel Physical and chemical properties of nickel History of nickel alloys

Relevance

Although the reserves of nickel ore in the lithosphere occupy only thirteenth place among metal ores, the importance of nickel today is no less than iron, aluminum, copper and other metals. Heat-resistant materials with unique properties have been created based on nickel. To date, the nickel industry has created more than 3,000 alloys. In the consumption structure, 80% of Ni is spent on alloys. 20% - for protective coatings. This metal gives the alloy valuable qualities. Nickel alloys are especially needed in aviation, energy, industrial chemistry, food industry, and electrical engineering. Radar and television cannot operate without nickel. Nickel plates have replaced cadmium plates in neutron beam choppers, generating high-energy neutron pulses. Nickel plates are used in ultrasonic units, as well as in modern telephones. Alloys with manganese additives (manganese nickel) are used in incandescent lamps and special rectifiers for electrode holders. Nickel guarantees excellent corrosion resistance. This is one of the main reasons for the widespread use of such a procedure as nickel plating. The protective layer of nickel, in addition to increasing corrosion resistance, additionally gives the product an aesthetic appearance.

Thermo-electrode alloys

The electrical resistivity of nickel wire changes with increasing temperature. Nickel is a determining factor in the formation of heat-resistant and thermo-electrode alloys. The electrical resistivity of nickel wire under normal conditions is at the level of 0.87 Ohmxmm2/m... Nickel-based alloys have the necessary qualities due to compliance with the production technology specified in regulatory documents (GOST, TU, international standards).

Alumel is a thermoelectrode alloy based on nickel 93−96%. Percentage composition

• Melting point: 1430−1450°C.
• Density: 8.67 g/cm3.
• The electrical resistivity of the wire is 0.33 Ohmxmm2/m.
• Temperature coefficient of linear expansion: 13.7×10-6/°C.

Kopel is a thermoelectrode copper-nickel alloy. Percentage composition

• Melting point: 1220−1290°C.
• Density: 8.9 g/cm3.
• The electrical resistivity of the wire is 0.47 Ohmxmm2/m.
• Temperature coefficient of linear expansion: 14×10-6/°C.

Chromel is a thermoelectrode alloy based on nickel 89−91%. Percentage composition

• Melting point: 1400−1500°C.
• Density: 8.72 g/cm3.
• The electrical resistivity of the wire is 0.68 Ohmxmm2/m.
• Temperature coefficient of linear expansion: 12.8×10-6/°C.

Constantan is a thermoelectrode copper-nickel alloy. Percentage composition

• Melting point: 1260 °C.
• Density: 8.9 g/cm3.
• The electrical resistivity of the wire is 0.5 Ohmxmm2/m.
• Temperature coefficient of linear expansion: 14.4×10-6/°C.

The production of thermocouple nickel wire alumel, copel, constantan, chromel is regulated by GOST 1790–77. Compensation wires made of nickel wire chromel, copel, constantan must meet the requirements of GOST 1791–67. The chemical composition of nickel and copper-nickel thermo-electrode alloys is regulated by GOST 492–2006.

Application

Alumel and chromel alloys are the most widely used materials for thermocouples. With their help, it is possible to accurately measure temperature over a wide range in oxidizing environments (up to t° 1200−1300°C), that is, under industrial process conditions. Nickel and copper alloys (copel, constantan) are used for rheostats. Such alloys contain 40–50% Ni, and the electrical resistance does not change with temperature.

Structural alloys

Jet technology would be impossible without special heat-resistant alloys Inconel and Hastelloy. Transport engineering is based on the use of such high-strength nickel alloys. Such alloys are used to produce chemical reactors, tanks, boilers and crucibles with high corrosion resistance. Nickel alloys play a vital role in the designs of gas turbine engines and nuclear boilers. They are used as high-temperature containment shells that protect uranium rods from corrosion in a nuclear reactor.

Percent composition of Inconel 600

Inconel 625

Hastelloy B-2

Hastelloy B-3

Hastelloy C-4

Provider

The products presented at the warehouse of the supplier "Auremo" have a quality certificate. The technical documentation reflects the chemical composition and mechanical qualities of the products. It’s easy to buy any metal products for large-scale production from us. We also offer optimal conditions for retail clients. A high level of service is rightfully the face of our company. For more detailed advice regarding supplies, you need to contact the manager, who is one of the leading experts in the nickel products market. Contact numbers and necessary details are posted in the appropriate section of the site. The courier service will deliver the order to any city.

Temperature coefficient values ​​for some metals

From the formula for the temperature coefficient of resistance we determine rt:

Example 6. Determine the resistance of an iron wire heated to 200°C, if its resistance at 0°C was 100 Ohms.

Example 7. A resistance thermometer made of platinum wire in a room with a temperature of 15°C had a resistance of 20 ohms. The thermometer was placed in the oven and after some time its resistance was measured. It turned out to be equal to 29.6 Ohms. Determine the temperature in the oven.

Electrical conductivity

So far, we have considered the resistance of a conductor as the obstacle that the conductor provides to the electric current. But still, current flows through the conductor. Therefore, in addition to resistance (obstacle), the conductor also has the ability to conduct electric current, that is, conductivity.

The more resistance a conductor has, the less conductivity it has, the worse it conducts electric current, and, conversely, the lower the resistance of a conductor, the more conductivity it has, the easier it is for current to pass through the conductor. Therefore, the resistance and conductivity of a conductor are reciprocal quantities.

From mathematics we know that the reciprocal of 5 is 1/5 and, conversely, the reciprocal of 1/7 is 7. Therefore, if the resistance of a conductor is denoted by the letter r, then the conductivity is defined as 1/r. Conductivity is usually symbolized by the letter g.

Electrical conductivity is measured in (1/Ohm) or in siemens.

Example 8. The conductor resistance is 20 ohms. Determine its conductivity.

If r = 20 Ohm, then

Example 9. The conductivity of the conductor is 0.1 (1/Ohm). Determine its resistance

If g = 0.1 (1/Ohm), then r = 1 / 0.1 = 10 (Ohm)

Electrical conductivity of aluminum

The specific conductivity of metals (also called specific electrical conductivity) refers to the ability of a metal to conduct electric current (measured in Ohms/m).
Although all metals are conductors, some conduct electricity better than others. The following is the conductivity of some metals and alloys at 20 °C:

Pure iron – 10,000,000

Methods for cutting metal under water Welding corner and T joints

DC welding generators Characteristics of power sources Electroslag welding of carbon steels

Electrodes for arc welding, surfacing, cutting Gas-electric welding in a carbon dioxide environment Self-propelled single-arc welding heads Electric welding arc and its properties As we know from Ohm's law, the current in a section of the circuit is in the following relationship:
I=U/R .
The law was derived through a series of experiments by the German physicist Georg Ohm in the 19th century. He noticed a pattern: the current strength in any section of the circuit directly depends on the voltage that is applied to this section, and inversely on its resistance. Later it was found that the resistance of a section depends on its geometric characteristics as follows: R=ρl/S ,

where l is the length of the conductor, S is its cross-sectional area, and ρ is a certain proportionality coefficient.

Thus, the resistance is determined by the geometry of the conductor, as well as by such a parameter as resistivity (hereinafter referred to as resistivity) - this is the name of this coefficient. If you take two conductors with the same cross-section and length and place them in a circuit one by one, then by measuring the current and resistance, you can see that in the two cases these indicators will be different. Thus, electrical resistivity is a characteristic of the material from which the conductor is made, or, to be even more precise, of the substance.

High conductivity materials

The most widespread materials of high conductivity include copper and aluminum (Superconducting materials, which have a typical resistance of 10-20 times lower than ordinary conductive materials (metals), are discussed in the section Superconductivity).

The advantages of copper, which ensure its widespread use as a conductor material, are as follows:

1. low resistivity;
2. sufficiently high mechanical strength;
3. corrosion resistance is satisfactory in most applications;
4. good workability: copper is rolled into sheets, strips and drawn into wire, the thickness of which can be increased to thousandths of a millimeter;
5. relative ease of soldering and welding.

Copper is most often obtained by processing sulfide ores. After a series of ore smelting and roasting with intense blasting, copper intended for electrical purposes must undergo a process of electrolytic purification.

Copper grades M1 and M0 are most often used as conductor material. M1 grade copper contains 99.9% Cu, and in the total amount of impurities (0.1%) oxygen should be no more than 0.08%. The presence of oxygen in copper worsens its mechanical properties. The best mechanical properties are found in M0 grade copper, which contains no more than 0.05% impurities, including no more than 0.02% oxygen.

Copper is a relatively expensive and scarce material, so it is increasingly being replaced by other metals, especially aluminum.

In some cases, alloys of copper with tin, silicon, phosphorus, beryllium, chromium, magnesium, and cadmium are used. Such alloys, called bronzes, with the correct composition, have significantly higher mechanical properties than pure copper.

Aluminum

Aluminum is the second most important conductor material after copper. This is the most important representative of the so-called light metals: the density of cast aluminum is about 2.6, and rolled aluminum is 2.7 Mg/m3. Thus, aluminum is approximately 3.5 times lighter than copper. The temperature coefficient of expansion, specific heat capacity and heat of fusion of aluminum are greater than those of copper. Due to the high values ​​of specific heat capacity and heat of fusion, heating aluminum to the melting point and transferring it to a molten state requires more heat than heating and melting the same amount of copper, although the melting point of aluminum is lower than that of copper.

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Aluminum has lower properties compared to copper - both mechanical and electrical. With the same cross-section and length, the electrical resistance of an aluminum wire is 1.63 times greater than that of a copper wire. It is very important that aluminum is less scarce than copper.

For electrical purposes, aluminum containing no more than 0.5% impurities, grade A1, is used. Even purer AB00 grade aluminum (no more than 0.03% impurities) is used for the manufacture of aluminum foil, electrodes and housings of electrolytic capacitors. Aluminum of the highest purity AB0000 has an impurity content of no more than 0.004%. Additives of Ni, Si, Zn or Fe at a content of 0.5% reduce the γ of annealed aluminum by no more than 2-3%. A more noticeable effect is exerted by Cu, Ag and Mg impurities, which, at the same mass content, reduce γ aluminum by 5-10%. Ti and Mn greatly reduce the electrical conductivity of aluminum.

Aluminum oxidizes very actively and becomes covered with a thin oxide film with high electrical resistance. This film protects the metal from further corrosion.

Aluminum alloys have increased mechanical strength. An example of such an alloy is Aldrey , containing 0.3-0.5% Mg, 0.4-0.7% Si and 0.2-0.3% Fe. In aldrey, the Mg2Si compound is formed, which imparts high mechanical properties to the alloy.

Iron and steel

Iron (steel), as the cheapest and most accessible metal, which also has high mechanical strength, is of great interest for use as a conductor material. However, even pure iron has a significantly higher resistivity compared to copper and aluminum; ρ steel, i.e. iron mixed with carbon and other elements is even higher. Ordinary steel has low corrosion resistance: even at normal temperatures, especially in conditions of high humidity, it quickly rusts; As the temperature rises, the corrosion rate increases sharply. Therefore, the surface of steel wires must be protected by a layer of more resistant material. Zinc coating is usually used for this purpose.

In some cases, to reduce the consumption of non-ferrous metals, the so-called bimetal . It is steel coated on the outside with a layer of copper, with both metals connected to each other firmly and continuously.

Sodium

Sodium metal is a very promising conductor material. Sodium can be obtained by electrolysis of molten sodium chloride NaCl in virtually unlimited quantities. From a comparison of the properties of sodium with the properties of other conductor metals, it is clear that the resistivity of sodium is approximately 2.8 times greater than ρ of copper and 1.7 times greater than ρ of aluminum, but due to the extremely low density of sodium (its density is almost 9 times less than the density of copper), a wire made of sodium for a given conductivity per unit length should be significantly lighter than a wire made of any other metal. However, sodium is extremely active chemically (it oxidizes intensely in air and reacts violently with water), which is why the sodium wire must be protected with a sealing sheath. The sheath must give the wire the necessary mechanical strength, since sodium is very soft and has a low tensile strength during deformation.

Literature on conductor resistivity

1. Kuznetsov M.I., “Fundamentals of Electrical Engineering” - 9th edition, revised - Moscow: Higher School, 1964 - 560 p.
2. Bachelis D. S., Belorussov N. I., Saakyan A. E. Electrical cables, wires and cords. Directory. - M.: Energy, 1971.
3. Gershun A.L. Cable // Encyclopedic Dictionary of Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg, 1890-1907.
4. R. Lakernik, D. Charlet. From copper to glass // Science and life. - 1986. - Issue. 08. - pp. 50-54, 2-3 pages, color insert.

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The resistivity of metals is a measure of their ability to resist the passage of electric current. This value is expressed in Ohm-meter (Ohm⋅m). The symbol for resistivity is the Greek letter ρ (rho). High resistivity means the material is a poor conductor of electrical charge.

Resistivity

Electrical resistivity is defined as the ratio between the electric field strength inside a metal and the current density within it:

where: ρ is the resistivity of the metal (Ohm⋅m), E is the electric field strength (V/m), J is the value of the electric current density in the metal (A/m2)

If the electric field strength (E) in a metal is very high and the current density (J) is very small, this means that the metal has high resistivity.

The reciprocal of resistivity is electrical conductivity, which indicates how well a material conducts electric current:

σ is the conductivity of the material, expressed in siemens per meter (S/m).

What is the resistance of copper and aluminum

Aluminum is a lightweight metal that can be easily machined and cast. It has high electrical conductivity: it ranks 4th after silver, copper and gold.

Important! Despite a number of advantages (low cost, light weight, ease of processing, and others), in the long term, aluminum wires are less profitable than copper wires.

In electrical engineering, 2 terms have meaning:

• Conductivity: Responsible for the transfer of current from one point to another. The higher the conductivity of a metal, the better it transmits electricity. At +20 degrees, the conductivity of copper is 59.5 million siemens per meter (S/m), aluminum - 38 million S/m. The conductivity of a copper cable is practically independent of temperature.
• Electrical resistance: the higher this concept, the worse the substance will pass current. The resistivity of copper is 0.01724-0.0180 μOhm/m, aluminum - 0.0262-0.0295.

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Aluminum cables are in demand no less than copper ones

In other words, copper has higher conductivity and lower resistance than aluminum.

Electrical resistance

Electrical resistance, one of the components of Ohm's law, is expressed in ohms (Ohms). It should be noted that electrical resistance and resistivity are not the same thing. Resistivity is a property of a material, while electrical resistance is a property of an object.

The electrical resistance of a resistor is determined by a combination of its shape and the resistivity of the material from which it is made.

For example, a wirewound resistor made from a long, thin wire has a higher resistance than a resistor made from a short, thick wire of the same metal.

At the same time, a wirewound resistor made of a high resistivity material has greater electrical resistance than a resistor made of a low resistivity material. And all this despite the fact that both resistors are made of wire of the same length and diameter.

To illustrate this, we can draw an analogy with a hydraulic system, where water is pumped through pipes.

• The longer and thinner the pipe, the greater the resistance to water.
• A pipe filled with sand will resist water more than a pipe without sand.

Wire resistance

The amount of wire resistance depends on three parameters: the resistivity of the metal, the length and diameter of the wire itself. Formula for calculating wire resistance:

where: R - wire resistance (Ohm) ρ - metal resistivity (Ohm.m) L - wire length (m) A - cross-sectional area of ​​the wire (m2)

As an example, consider a nichrome wirewound resistor with a resistivity of 1.10×10-6 Ohm.m. The wire has a length of 1500 mm and a diameter of 0.5 mm. Based on these three parameters, we calculate the resistance of the nichrome wire:

R=1.1*10 -6 *(1.5/0.000000196) = 8.4 Ohm

Nichrome and constantan are often used as resistance materials. Below in the table you can see the resistivity of some of the most commonly used metals.

Surface resistance

The surface resistance value is calculated in the same way as the wire resistance. In this case, the cross-sectional area can be represented as the product of w and t:

For some materials, such as thin films, the relationship between resistivity and film thickness is called sheet sheet resistance RS: where RS is measured in ohms. For this calculation, the film thickness must be constant.

Often, resistor manufacturers cut tracks into the film to increase resistance to increase the path for electrical current.

Other properties

Today, aluminum is produced almost twice as much as copper. And in comparison with all mined metals, it is second only to steel. This confirms that every year the electrical industry is increasing its use. This is explained by a number of reasons, which we will consider further.

Electrical performance of aluminum

According to the International Annealed Copper Standard (IACS), the latter is rated as 100% conductive. According to the above information, aluminum conducts electricity at only 61% equivalent to the generally accepted standard.

Thus, an equal percentage will only be achieved with larger cross sections. Since copper is significantly heavier than aluminum, such an “increased” conductor in mass will still be lighter than copper.

Comparative density of aluminum and copper Source aluminum-guide.com

This fact has been proven through complex mathematical calculations, the result of which shows that 1 kg. aluminum provides equal conduction speed to that of 2 kg. copper Therefore, if certain technical conditions for the size of conductors do not require this, copper is replaced with aluminum.

Healthy! If for use in home wiring the weight of an electric wire does not have a special role, then when used on overhead power lines (overhead power lines), the weight of the current-carrying conductors has a significant effect. Therefore, take the one that is lighter, that is, aluminum.

Strength index

Provided the cross-section is the same, copper conductors are stronger than aluminum conductors. Although, this figure can be easily increased by alloying or thermomechanical treatment, or by increasing the cross-section.

The table shows that aluminum is 2 times weaker in tensile strength Source aluminum-guide.com

The values ​​​​given in the table show that aluminum conducts current, but is inferior to copper in terms of “break strength”. However, it is able to withstand its own weight and does not overload the overhead power line supports as much as copper.

In addition, extruding aluminum involves obtaining cross-sections of complex shapes, which cannot be obtained from steel. Based on such objective reasons, new elements can be designed in such a way that they will be the most effective in comparison with acceptable analogues from other materials.

Properties of resistive materials

The resistivity of a metal depends on temperature. Their values ​​are usually given for room temperature (20°C). The change in resistivity as a result of a change in temperature is characterized by a temperature coefficient.

For example, thermistors (thermistors) use this property to measure temperature. On the other hand, in precision electronics, this is a rather undesirable effect. Metal film resistors have excellent temperature stability properties. This is achieved not only due to the low resistivity of the material, but also due to the mechanical design of the resistor itself.

Many different materials and alloys are used in the manufacture of resistors. Nichrome (an alloy of nickel and chromium), due to its high resistivity and resistance to oxidation at high temperatures, is often used as a material for making wirewound resistors. Its disadvantage is that it cannot be soldered. Constantan, another popular material, is easy to solder and has a lower temperature coefficient.

Advantages and disadvantages of aluminum wiring

The widespread use of aluminum wiring was practiced in old buildings. The main criterion in those days was easy availability and low cost of metal. The possibility of a lack of cable cross-section was not considered in those days due to the lack of electrical household appliances in the apartments of average citizens.

Types of SIP cable for connecting a cottage Source yandex.net

Positive factors

The low weight of aluminum wire makes it popular when installing high-voltage power lines. This condition has already been stated earlier, so let’s consider a number of other aspects:

• Relatively low price of metal and products made from it. This factor plays a role when laying long lines. For example, to fully electrify a country house, more than 1,000 m of wire may be needed.
• Resistance to chemical oxidation. This condition is relevant given that the cores are hidden by plastic insulation.
• Durability of areas without insulation. As mentioned earlier, a protective film is formed on the surface of aluminum, which prevents the occurrence of oxidative processes.

High-voltage line with a voltage of 35 kV Source cdn.pixabay.com