Hello.
Any modern multimedia device (computer, laptop, player, phone, etc.) has audio outputs: for connecting headphones, speakers, a microphone, and other devices. And it would seem that everything is simple - I connected a device to the audio output and it should work.
But everything is not always so easy ... The fact is that the connectors on different devices are different (although sometimes they are very similar to each other)! The vast majority of devices use connectors: jack, mini-jack and micro-jack (jack in English means "jack"). That's about them and I want to say a few words in this article.
Mini-Jack connector (diameter 3.5 mm)
Rice. 1. mini jack
Why did I start with a mini-jack? It is simply the most popular connector that can only be found in modern technology. Found in:
- - headphones (moreover, both with a built-in microphone and without it);
- - microphones (amateur);
- - various players and phones;
- - speakers for computers and laptops, etc.
Connector Jack (diameter 6.3 mm)
It is much rarer than mini-Jack, but nevertheless quite common in some devices (more, of course, in professional devices than in amateur ones). Eg:
- microphones and headphones (professional);
- bass guitars, electric guitars, etc.;
- sound cards for professionals and other audio devices.
Micro-Jack connector (diameter 2.5mm)
The smallest connector listed. Its diameter is only 2.5 mm and it is used in the most portable technology: phones and players. True, recently, even they began to use a mini-jack in order to increase the compatibility of the same headphones with PCs and laptops.
Mono and stereo
Rice. 4. 2 contacts - Mono; 3 pins - stereo
Please also note that the jack connectors can be either mono or stereo (see Fig. 4). In some cases, this can cause a lot of problems ...
For most users, the following will suffice:
- mono - this means for one sound source (you can only connect a mono speaker);
- stereo - for several sound sources (for example, left and right speakers, or headphones. You can connect both mono and stereo speakers);
- quad - practically the same as stereo, only two more sound sources are added.
Headset jack in laptops for connecting headphones with a microphone
In modern laptops, a headset jack is increasingly common: it is very convenient for connecting headphones with a microphone (there is no extra wire). By the way, on the body of the device, it is usually indicated as follows: a picture of headphones with a microphone (see Fig. 5: on the left - microphone outputs (pink) and headphones (green), on the right - a headset jack).
By the way, the plug for connecting to such a connector should have 4 pins (as in Fig. 6). I talked about this in more detail in my previous article:
Rice. 6. Plug for connecting to the headset jack
How to Connect Speakers, Microphone or Headphones to Computer
If you have the most common sound card on your computer, then everything is quite simple. On the back of the PC, you should have 3 outputs, as in fig. 7 (at least):
- Microphone (microphone) - marked in pink. Needed to connect a microphone.
- Line-in (blue) - used, for example, to record sound from some device;
- Line-out (green) - this is a headphone or speaker output.
Problems most often occur when, for example, you have headset headphones with a microphone and there is no such output on your computer ... In this case, there is dozens of different adapters : there is, including an adapter from the headset jack to the usual ones: Microphone and Line-out (see Fig. 8).
Also, a fairly common problem is the lack of sound (most often after reinstalling Windows). The problem in most cases is due to the lack of drivers (or the installation of the wrong drivers). I recommend using the recommendations from this article:
You may also be interested in the following articles:
- - connecting headphones and speakers to a laptop (PC):
- - extraneous sound in speakers and headphones:
- - quiet sound (how to increase the volume):
Hello people!
Everyone has headphones, and sooner or later, every headphone has problems. 99% of these problems are related to the connector. The thermoplastic connector gradually becomes softer, loosens, peels off from the wire. And it protects the wire at the exit point from the thermoplastic worse and worse. We will repair, or rather just solder a new connector.
When my beloved wife's left ear stopped working on her favorite synheisers, she looked at me with a look when everything was clear without words, and the next day after work I went to Savelovsky Bazaar in Moscow. There are several stalls with slots there. It’s just that it’s convenient for me to go there on the way, but the matter was urgent, the work was standing without headphones. Seeing exactly the same connectors as described here for 300 - 350 rubles a piece, made round eyes, ofigef saying "hop-hop?" I heard - “three hundred, this is a sinheiser !!!”. Well, we know this sinheiser. I took a 20-ruble plastic connector as a temporary hut: 
and on the same evening I got on Ali and found the described lot of four pieces for 2.35 monetary units of a distant overseas country. In rubles, it was carried out in the amount of 152.31, that is, 38 rubles and 8 kopecks per piece. That is, almost 8 times cheaper than the market. It was this glaring difference in price that prompted me to write a review on such a trifle.
We arrived quickly. August 23 evening order - September 3 morning in the mailbox. 
There are 4 connectors in different colors in the package. The seller can also put any specific color that you like, you must ask in the order. Connectors in sealed individual bags. A piece of solder is attached to each, 20 times more than it is necessary to solder it, and five centimeters of black 4 mm heat shrink.
At the request of our beloved wife, we will open and solder the red one. 
The contact part is slightly elongated so that it can be plugged into modern smart phones with a recessed socket, although with a slight thickening. The letters are applied qualitatively, they are not scraped off with a fingernail. 
.A little unusual arrangement inside, no usual petals, but there seems to be no particular problems. All metal parts are covered with something yellow, we have to believe that it is gold. Irradiated with the help of LTI-120 very easily. The applied solder is quite fusible, with flux. 
Soldered also bases of problems. Outside, I put heat shrink on everything and twisted the cap. It turned out nice. 
The cat is on vacation in the country, today without him.
Thank you for your attention!
I plan to buy +59 Add to favorites Liked the review +42 +82Greetings to all who looked at the light. The review will focus, as you probably already guessed, on very useful adapters / adapters / extension cords for connecting to various audio equipment. In the review, I will try to talk about what a headset and headphones are, how they differ and in what ways they can be connected to different connectors. If you are interested, you are welcome under cat.
General view of the monitored adapters: 
A few words about cables and adapters:
All monitored adapters are designed for the TRS audio connector, which stands for English as Tip (tip), Ring (ring), Sleeve (sleeve) in accordance with the shape of the contacts. Despite such a short name, another name has taken root among the people - "Jack", which in English means "nest". There are quite a few varieties of this connector, both in terms of the number of contacts and in size (photo from the Internet): 
It is clearly seen from the picture that Jack is the largest, microJack is the most compact, by analogy with SIM cards, where the usual SIM cards for smartphones are considered microSIM and even nanoSIM.
These connectors are intended mainly for connecting cables and transmitting an audio signal, but there are also implementations for transmitting a video signal (for example, a reversing camera for GPS recorders), or for connecting low-power power sources (PSU with a two-pin TS / micro / miniJack connector). On my own behalf, I’ll add that older ones (Jack) are found in professional sound reproducing equipment, for the most part due to a more reliable design and better electrical characteristics, although with the ubiquity of digital sound, they are gradually losing their relevance.
In this review, I will talk about the four most common options for home use:
- three-pin miniJack 3.5mm - hereinafter referred to as miniJack (TRS) 3.5mm
- four-pin miniJack 3.5mm - hereinafter referred to as miniJack (TRRS) 3.5mm
- three-pin microJack 2.5mm - hereinafter miniJack (TRS) 2.5mm
- four-pin microJack 2.5mm - hereinafter referred to as miniJack (TRRS) 2.5mm
It is easy to guess that they differ in diameter (2.5mm vs 3.5mm) and the presence of an additional (fourth) contact, which the headset needs to control buttons and a microphone. I would like to note that headphones and a headset are completely different things, and the main difference between them is that the latter have a built-in microphone and control buttons (volume, calls). Thanks to this, it is possible to control some smartphone functions through the headset by pressing the appropriate buttons. Headphones, in turn, do not have buttons and are only suitable for playing an audio signal. You can determine what exactly you are using by visual signs: on one of the wires going to the “ears” there is a control block with buttons, a four-pin connector (TRRS), and when connected to a gadget, a headphone icon with a microphone is displayed in the notification area . This is more clearly shown in the picture below (photo from the Internet): 
For those who are not in the know, the principle of operation of the headset control buttons is quite simple: inside the case there is a small control board, which, with different combinations of buttons, produces different resistance. There are only two wires at the output, one of which is common with the headphones (ground). The smartphone reads the resistance and issues the desired command. The same principle works, for example, steering control buttons in the car.
One of the possible schemes for implementing a three-button headset: 
Everything would be fine, but there is one caveat - there are two main headset wiring standards on the market - OMTP (old) and CTIA (new). If the soldering standards of the headset and the smartphone are the same, all functions will work; if they do not match, the sound will be “muffled”, the buttons and the microphone will not work. Most modern smartphones and headsets are made according to the new CTIA standard, but there are also options with the old wiring standard.
I would also like to note an important feature: in the four-pin jack (TRRS) without any problems and consequences for the gadget, all headphones with a three-pin pin (TRS) work, i.e. when connecting headphones to a smartphone, the operation of the systems is not disturbed. In the opposite case, i.e. when connected to a three-pin socket (TRS), a headset with a four-pin pin (TRRS), for example, a headset to a tablet, there are no failures in the electronics either, only additional (push-button) functions of the headset and microphone are missing. As they say, backward compatibility is preserved.
This concludes the introductory part. Below in the review, adapter options for both headsets and headphones will be considered.
Extension cable miniJack (TRRS) 3.5mm (male) ->
The first in line is a high-quality miniJack (TRRS) 3.5mm extension cable (male) -> miniJack (TRRS) 3.5mm (female): 
This extension cable features a 90° angled plug, a very robust design and full support for the CTIA (Samsung) headset wiring standard. In other words, using this extension cord, all the functions of the headset will be preserved when connected to a modern smartphone.
I have had this extension for a long time. I bought it after purchasing my "old man" Samsung Galaxy S3 (SGS3) in order to minimize the load on the smartphone and headset connector when listening to music. If I'm not mistaken, it was supplied in a similar bag: 
Despite the meager packaging, the extension cord is of high quality and has been serving for many years, although now I do not use it so often. The cable is marked 2725 AWM 80C 30V VW-1 LL58663 CU CSA: 
You can see a little more about decoding the markings in my previous review of USB 3.0 cables. I will only note that the cable has been certified, the cable manufacturer is Cablemax, the cable type is Multiple-conductor cable using non-integral jacket. As mentioned earlier, there are absolutely no complaints about the device: the connector/socket shells are fused into a strong insulator, the cable is thick enough, the connector contacts are gold-plated (coated with titanium nitride) to protect against oxidation. The main purpose of this extension cord is to protect the connector, as well as the headset / headphone wires from bending. On modern smartphones with the CTIA headset wiring standard (“under Samsung”), when using this extension cord, all headset functions are preserved. For example, when listening to music, you can switch tracks forward / backward, stop / play a track, and answer an incoming call using the microphone built into the headset. No flaws were found, so I definitely recommend to buy!
Extension miniJack (TRRS) 3.5mm (male) -> miniJack (TRRS) 3.5mm (female):
The next in line is a similar miniJack (TRRS) 3.5mm (male) -> miniJack (TRRS) 3.5mm (female) extension cable, but already under the OMTP headset wiring standard (the old standard or “for Nokia”): 
I bought this extension cord out of ignorance, so the headset functions are not available in the SGS3 smartphone. If I'm not mistaken I bought
In appearance it is similar to the previous one - the same four contacts both on the plug and in the socket, but the main difference lies in the internal wiring (see "Introduction"). In this regard, when the headset is connected to modern smartphones, additional functions do not work, i. the headset turns into regular headphones, the sound becomes “muffled”.
There are no special comments on the quality, except that there is no marking on the cable, and its thickness is much less than the previous one. In addition, the plug here is not angular: 
Despite the rather frail cable, the connector/jack housings are fused into a fairly strong insulator, and the connector contacts themselves are gold-plated (coated with titanium nitride) to protect against oxidation.
In general, the extension cord is good, but only relevant for older phone models.
Extension cable miniJack (TRS) 3.5mm (male) ->
This is one of the simplest extension cords, designed to connect headphones or a headset to various electronic gadgets or a computer. It is intended for audio signal transmission only, additional functions of the headset will not work, because. the fourth wire (contact) is missing. This extension has a three-pin plug/socket (TRS), cable length 3m: 
I bought
As far as I remember, an extension cord was supplied in a simple bag: 
Despite its simplicity, the quality of the extension cord is excellent: the cable is covered with a fabric braid to protect it from stretching, the connector/jack housings are fused into a sufficiently strong insulator, and the connector contacts themselves are gold-plated (coated with titanium nitride) to protect against oxidation. I used it for a long time when connecting the headset from the SGS3 smartphone (“earbuds”) to the computer system unit, since the length of the headset wires was a little less than a meter and they were simply not enough. The extension cable has repeatedly withstood the impact of a computer chair roller, there were no wire breaks, so if you are looking for a sufficiently long and high-quality headphone extension cable, I recommend it!
Extension miniJack (TRS) 3.5mm (male) -> miniJack (TRS) 3.5mm (male):
This is a rather specific, but sometimes indispensable cable for connecting various audio signal sources to radio / tape recorders / computer: 
I bought this cable a long time ago in local stores. In appearance, this one is suitable, which you can buy
One of the main home applications of this extension cable is to connect capture cards to the input of a computer sound card, i.e. from the audio output of the board to the audio input of the sound card. Now this lesson has somewhat lost its relevance, but in the distant 2000s it was relevant. At that time I had a TV tuner (video capture card) LifeView 2000, for connection I just needed a monitored cable (it was included). Another application is the digitization of audio recordings, but at this time this activity is devoid of any meaning.
Cable length - 70cm, at both ends - three-pin miniJack (TRS) 3.5mm: 
There are practically no complaints about the quality, except that the connector contacts are not gold-plated. The cable is strong enough, the connectors are firmly fused. At one time, I used it in a car, first connecting a simple MP3 player, and then a smartphone to the AUX input of a standard head unit (radio), which did not support MP3 format and external drives (memory cards and flash drives): 
The quality was quite satisfactory, but the connection was not very convenient. Devices had to be recharged, and the loose wire was a nuisance. Therefore, after some time I purchased an FM modulator, and when I moved to another city, I finally realized that it was easier to take a normal radio tape recorder, because all kinds of pickups from trolleybus tracks nullified the use of the modulator. I apologize for a small opus, but I used this extension cord quite often: both in the heat and in the cold, so I vouch for the quality.
Splitter / extension miniJack (TRS) 3.5mm (male) ->
Next comes a rather specific splitter / extension miniJack (TRS) 3.5mm (male) to two miniJack (TRS) 3.5mm jacks (mother): 
You can buy this extension
Unfortunately, the connector/splitter sockets are three-pin, allowing only stereo sound to be transmitted. When you connect a headset, it will only work as headphones. Ideal for connecting two pairs of headphones to a tablet for shared viewing / listening to media content in public places, for example, on a train, commuter train.
If I'm not mistaken, an extension cable was supplied in a simple bag: 
Despite the limited functionality, the workmanship is at a very high level: the connector/socket shells are fused into a strong, but at the same time elastic insulator (somewhat reminiscent of silicone), the cable is thick, but very soft, the connector contacts are gold-plated (coated with titanium nitride) for protection against oxidation: 
I bought this splitter / extension cable to quickly connect headphones and home-made active speakers to a computer. No complaints were found during operation, the wires did not break, so I recommend it for purchase!
Splitter miniJack (TRS) 3.5mm (male) -> 2 * miniJack (TRS) 3.5mm (female):
A more compact version of the previous splitter, but the design is more frail. From one end there is a miniJack (TRS) 3.5mm plug (male): 
On the other end there are two miniJack (TRS) 3.5mm sockets (mother): 
I bought this adapter offline, but recently I came across an improved version with gold-plated contacts. In the GearBest store, a lot of ten "improved" adapters costs as much as one on Ali. You can buy
Despite the simplicity of the design, this splitter has 4 disadvantages: the case is made of soft plastic, in some cases the height of the case interferes with the adjacent socket, the contacts of the connectors are not gold-plated, the flimsy design of the internal petals (current collectors) in the sockets. Despite the disadvantages, this splitter worked flawlessly until it was replaced with the previous version, but over time, a small backlash of the pin appeared. In this regard, given the meager cost, it is suitable only as a temporary solution.
Adapter / adapter microJack (TRS) 2.5mm (male) -> miniJack (TRS) 3.5mm (female):
A very useful adapter for connecting popular headphones with a 3.5mm miniJack (TRS) jack to devices with a 2.5mm microJack (TRS) jack: 
It will seem strange to many, but many old tablets have just a 2.5mm microJack (TRS) jack. I didn’t use this adapter too often, so it’s still in its original package: 
In the GearBest store, there is already another product under this SKU, but you can buy
For those who do not understand, there is a 2.5mm pin on the left, and a recessed 3.5mm jack on the right for connecting modern headphones / microphones: 
The quality of the adapter is average: the case is made of soft plastic, the contacts of the connectors are not gold-plated, and the design looks flimsy. Suitable only for infrequent connections.
Adapter / adapter miniJack (TRRS) 3.5mm (male) -> microJack (TRRS) 2.5mm (female):
Another useful adapter / adapter, but designed to connect headphones / headset with a microJack (TRRS) 2.5mm connector to standard 3.5mm jacks: 
You can buy
In terms of workmanship, everything is excellent: a durable metal case, gold-plated contacts, wiring for the modern CTIA standard (“under Samsung”). The dimensions of the adapter are very compact, the case is one-piece, non-separable. On the one hand, a four-pin 3.5mm pin: 
On the other hand, a recessed four-pin 2.5mm socket: 
Compared to the previous adapter: 
This adapter is used to connect large 2.5mm plug headphones purchased at JD's lavish sale for a dollar or so. The headphones themselves are connected to the laptop. In the work for a year and a half, the flight is excellent, so I recommend it!
Case for in-ear or headset:
Well, the last one on the review is a very convenient case for storing various small things: 
It was bought for a promotion for 10 cents at some sale of the GearBest store. You can buy
If I'm not mistaken, then this lot often appears in the "sale" section and just a couple of weeks ago it was just 10 cents (October 9).
I use this case to store the Tennmak headset with the very first extension cord from the review: 
On one of the cups there is a special pocket: 
Despite its compact size, two headsets are easily included in this case. There are no special comments on the quality of sewing: the threads do not stick out, no skin defects were found, the lock is strong. I would like to note that the cover is covered with leatherette (not natural), thanks to which it has a pleasant appearance and is somewhat resistant to moisture.
The inner diameter of the case is about 70mm, here is a comparison with a box of matches: 
Two boxes of matches fit easily inside the case. In general, even for the full price, it is worth the money, so I definitely recommend it!
In total, these adapters make it much easier to work with devices that have less common connectors, and their compact dimensions allow you to carry them with you all the time. All adapters were purchased at different times and used for quite a long time, see recommendations under each lot
I plan to buy +15 Add to favorites Liked the review +14 +35Pinout of various Jack (TRS) connectors
Jack connector aka TRS, a common connector for transmitting an audio signal with ring contacts.
There are three standard sizes for this connector.
- Jack 6.35 mm (sometimes called a big jack).
- Mini-jack 3.5 mm
- Micro-jack 2.5 mm.
Also, the connectors differ in the number of contacts (rings):
- Most often it has three pins and is correctly called TRS (stereo signal)
- The variant with two is called TS (mono)
- Four TRRS variant (stereo + microphone\button\etc)
- With five pins TRRRS (stereo + video, etc.)
The standard stereo jack (TRS) has the following pinout:
In professional sound engineering, a balanced connection is often used, then the pin assignment is different:
For headsets of mobile phones today, the TRRS connector (four pins) of size 3.5mm is most often used. For this connector, until 2012, manufacturers usually used a combination of contacts corresponding to the OMTP (Open Mobile Terminal Platform) standard. After 2012, the CTIA (Cellular Telephone Industries Association) sequence became standard practice among electronics manufacturers. Pinout of both standards in the figure below.
When you connect an OMTP headset to a CTIA device in standard mode, the ground is unused. The sound of the headphones at the same time is heard as a characteristic "deaf" mono with a large excess of medium frequencies. When you press the headset button, the microphone closes to the ground contact and the OMTP standard headset headphones work according to the standard scheme in stereo mode.
There are also many possible non-standard pinouts for this connector. Below is the pinout of some plugs from Apple.
In some Motorola phones, a four-pin 2.5mm jack (TRRS) plug with a non-standard pinout was used for the headset:
In theory, the diameter of the conductors should correspond to the declared parameters. For example, if it is indicated on the marking that the cable is 3 x 2.5, then the cross section of the conductors must be exactly 2.5 mm 2. In fact, it turns out that the real size can differ by 20-30%, and sometimes more. What does it threaten? Overheating or melting of insulation with all the ensuing consequences. Therefore, before buying, it is advisable to find out the size of the wire in order to determine its cross section. How exactly to calculate the cross section of the wire in diameter and we will find out further.
How and with what to measure the diameter of the wire (wire)
To measure the diameter of the wire, a caliper or micrometer of any type (mechanical or electronic) is suitable. It is easier to work with electronic ones, but not everyone has them. It is necessary to measure the core itself without insulation, therefore first move it away or remove a small piece. This can be done if the seller allows. If not, buy a small piece for testing and take measurements on it. On a conductor stripped of insulation, measure the diameter, after which you can determine the actual cross-section of the wire according to the dimensions found.
Which measuring device is better in this case? If we talk about mechanical models, then a micrometer. It has higher measurement accuracy. If we talk about electronic options, then for our purposes they both give quite reliable results.
If you don't have a caliper or micrometer, take a screwdriver and a ruler with you. You will have to strip a pretty decent piece of the conductor, so this time you are unlikely to do without buying a test sample. So, remove the insulation from a piece of wire 5-10 cm. Wind the wire around the cylindrical part of the screwdriver. The coils are laid close to each other, without a gap. All turns must be complete, that is, the "tails" of the wire must stick out in one direction - up or down, for example.
The number of turns is not important - about 10. It can be more or less, it's just easier to divide by 10. You count the turns, then apply the resulting winding to the ruler, aligning the beginning of the first turn with the zero mark (as in the photo). Measure the length of the section occupied by the wire, then divide it by the number of turns. Get the wire diameter. It's that simple.
For example, let's calculate the size of the wire shown in the photo above. The number of turns in this case is 11, they occupy 7.5 mm. We divide 7.5 by 11, we get 0.68 mm. This will be the diameter of this wire. Next, you can search for the cross section of this conductor.
We are looking for a wire cross-section by diameter: formula
The wires in the cable are circular in cross section. Therefore, in the calculations we use the formula for the area of a circle. It can be found using either the radius (half of the measured diameter) or the diameter (see formula).
Determine the cross section of the wire by diameter: formula
For example, let's calculate the cross-sectional area of the conductor (wire) according to the size calculated earlier: 0.68 mm. Let's use the radius formula first. First we find the radius: we divide the diameter by two. 0.68 mm / 2 = 0.34 mm. Next, we substitute this number into the formula
S \u003d π * R 2 \u003d 3.14 * 0.34 2 \u003d 0.36 mm 2
It is necessary to count as follows: first we square 0.34, then we multiply the resulting value by 3.14. We got the cross section of this wire 0.36 square millimeters. This is a very thin wire that is not used in power networks.
Let's calculate the cable cross-section by diameter using the second part of the formula. It should be exactly the same value. The difference may be in thousandths due to different rounding.
S \u003d π / 4 * D 2 \u003d 3.14 / 4 * 0.68 2 \u003d 0.785 * 0.4624 \u003d 0.36 mm 2
In this case, we divide the number 3.14 by four, then square the diameter, multiply the two resulting numbers. We get a similar value, as it should be. Now you know how to find out the cable cross-section by diameter. Whichever of these formulas is more convenient for you, use that one. No difference.
Correspondence table for wire diameters and their cross-sectional area
It is not always desirable or possible to carry out calculations in a store or in the market. In order not to waste time on calculations or not to make a mistake, you can use the table of wire diameters and cross-sections, which contains the most common (standard) sizes. You can write it down, print it out and take it with you.
| Conductor diameter | Conductor cross section |
|---|---|
| 0.8mm | 0.5 mm2 |
| 0.98 mm | 0.75 mm2 |
| 1.13mm | 1 mm2 |
| 1.38mm | 1.5 mm2 |
| 1.6mm | 2.0 mm2 |
| 1.78mm | 2.5 mm2 |
| 2.26 mm | 4.0 mm2 |
| 2.76mm | 6.0 mm2 |
| 3.57mm | 10.0 mm2 |
| 4.51 mm | 16.0 mm2 |
| 5.64 mm | 25.0 mm2 |
How to work with this table? As a rule, the cables have a marking or a tag on which its parameters are indicated. It indicates the cable marking, the number of cores and their cross section. For example, 2x4. We are interested in the parameters of the core, and these are the numbers that come after the “x” sign. In this case, it is stated that there are two conductors having a cross section of 4 mm 2 . So we will check whether this information is true.
How to work with a table
To check, measure the diameter using any of the methods described, then refer to the table. It states that with such a cross section of four square millimeters, the wire size should be 2.26 mm. If your measurements are the same or very close (there is a measurement error, since the devices are not ideal), everything is fine, you can buy this cable.
But much more often, the actual diameter of the conductors is much less than the declared one. Then you have two ways: look for a wire from another manufacturer or take a larger section. Of course, you will have to overpay for it, but the first option will require a fairly long period of time, and it’s not a fact that you will be able to find a cable that meets GOST.
The second option will require more money, since the price significantly depends on the declared section. Although, not a fact - a good cable, made according to all standards, can cost even more. This is understandable - the cost of copper, and, often, for insulation, subject to technology and standards, is much higher. Therefore, manufacturers are cunning, reducing the diameter of the wires - in order to reduce the price. But such savings can turn into disaster. So be sure to take measurements before buying. Even trusted suppliers.
And one more thing: inspect and feel the insulation. It should be thick, solid, have the same thickness. If, in addition to changing the diameter, there are also problems with insulation, look for a cable from another manufacturer. In general, it is desirable to find products that meet the requirements of GOST, and not made according to TU. In this case, there is hope that the cable or wire will last a long time and without problems. Today this is not easy to do, but if you breed or, quality is very important. That's why it's probably worth looking into.
How to determine the cross section of a stranded wire
Sometimes conductors are used stranded - consisting of many identical thin wires. How to calculate the wire cross-section by diameter in this case? Yes, exactly the same. Take measurements / calculations for one wire, count their number in a bundle, then multiply by this number. So you will find out the cross-sectional area of \u200b\u200ba stranded wire.
