The article considers the main criteria for choosing a cable section, gives examples of calculations.

In the markets, you can often see hand-written signs indicating which cable the customer needs to purchase depending on the expected load current. Do not believe these signs, as they mislead you. The cable cross-section is selected not only by operating current, but also by several parameters.

First of all, it must be borne in mind that when using a cable at the limit of its capabilities, the cable cores heat up several tens of degrees. The current values ​​shown in the figure assume heating of the cable cores to 65 degrees at an ambient temperature of 25 degrees. If several cables are laid in one pipe or tray, then due to their mutual heating (each cable heats all other cables), the maximum allowable current is reduced by 10 - 30 percent. Also, the maximum possible current is reduced ...

Many, making repairs, do not even think about the need to order a project for the electrical network of their apartment. And in vain. If there is a power grid project made by a qualified designer, the likelihood of making mistakes in the construction of the network is significantly reduced.

A qualified electrician can often make a good electrical network for a small apartment by selecting the required cables for the permissible current, but in the future the lack of a project often leads to big trouble. Problems appear when a fault occurs in the wiring. Finding a malfunction in a furniture-laden apartment in the absence of a project can be so difficult that you first have to move all the furniture in search of the missing contact, and then hammer the walls in a well-repaired room. If you are repairing a large apartment with long electric lines ...

Until recently, two types of electric underfloor heating could be found on sale: based on heating cables and heating mats. They did not have differences in the principle of operation, and the choice between them depended only on the features of the room in which floor heating is required.

A few years ago, a brand new infrared film-based warm floor appeared on the market. Manufacturers unanimously declare the numerous advantages of this type of electric underfloor heating. Many people who carry out repairs in their apartments are interested in the question: “What kind of electric underfloor heating to lay?”.

The main argument of sellers in favor of heating films is the beneficial effect of infrared radiation on the human body. Indeed, medical research has established the healing properties of infrared radiation. It is used in physiotherapy to treat many diseases ...

One of the significant inventions of the XX century is considered to be the invention of the transistor, which came to replace electronic tubes.

For a long time, lamps were the only active component of all electronic devices, although they had many shortcomings. First of all, it is a large power consumption, large dimensions, short life and low mechanical strength. These shortcomings were felt more and more sharply with the improvement and sophistication of electronic equipment.

A revolutionary revolution in radio engineering took place when outdated lamps were replaced by semiconductor amplifying devices - transistors, devoid of all the mentioned disadvantages.The first operational transistor was born in 1947, thanks to the efforts of employees of the American company Bell Telephone Laboratories. Their names are now known throughout the world. These are scientists - physicists W. Shockley, D. Bardin and W. Brighten ...

Any construction begins with the project. Suppose we have two brick cars, a cement car, a car of various pipes, and a floor of a car of electric cables. What, first of all, do we need to do to build a house, a production hall or a stadium from all this diverse material?

During the construction, hundreds of people of various specialties simultaneously perform their work, and as a result of their joint work, a beautiful and convenient building is erected. In order to make this possible, before the construction of any building or structure, the sacrament of design takes place.

Long before the start of construction, architects and designers come to the place of future construction. Architects are primarily responsible for the beauty of the future building. They are needed, first of all, where special requirements are made to the facades of buildings and their interior decoration ...

When mounting electrical cabinets, sometimes it is necessary to mount rather massive components on the mounting panel that cannot be fastened tightly, because they need to be removed from time to time for various reasons - for replacement, for maintenance, etc., for example, electricity meters (meters ), frequency drives, etc. Usually they are fixed with screws.

For this, it is necessary to provide threaded holes in the mounting panel so that when they are removed, the entire panel in the mounted cabinet must not be removed, so that the fixing nuts can be reached from the back of the panel.

With their small diameters, a panel made of a thin sheet is enough to bulge and cut the M3, M4 thread into them, but for greater bearing capacity with the M5, M6 threads this way you can’t do, you cannot make such a thread in a thin sheet of a panel. It is necessary to put threaded bushings in these places. At the next trip, the store in the fastener department, I came across threaded rivets ...

Often there is a need for partial or complete replacement of electrical wiring after an already completed repair. Wallpaper is pasted, and there is no way to lay cables under the plaster. Floor and ceiling skirting boards come to the rescue, having cavities in which the cable can be freely placed.

The figure shows a floor plinth specially designed for laying a cable in it. This skirting board has a detachable cover that allows you to lay the cable in it without removing the skirting board.

In the simplest case, sockets can be located directly above the baseboard. Such a need often arises, for example, after moving furniture in the apartment, when the furniture closes existing outlets. Special cavities for cables can also be in casings for doors and windows. Ample opportunities for hidden cable management are provided by ceiling skirting boards, which are currently widely used ...

Continuation of the article about solderless breadboards. If the first part of the article focuses on the review of prototyping boards and a description of their device, now we will consider some useful subtleties and nuances that you need to know when working with such prototyping boards.

If the instructions of the solderless breadboard say that the diameter of the wire inserted into the contacts is 0.4 - 0.7 mm, then you should not try to insert the conclusions of parts that are thicker than the specified value. This will lead to weakening and wear of the contacts.If the need arises for the use of such parts, it is better to solder the wires of the specified diameter to the thick terminals, or simply wrap them. Naturally, the wire should be without insulation.

Solderless breadboards are sold in two trim levels: with wires - jumpers and without them. In the first version, the board turns out to be a little more expensive, but it doesn’t matter if you managed to buy a separate board ...

With the modern development of laser-ironing technology, making a printed circuit board at home is so simple that it’s even funny to talk about it. It is enough to print a picture with conductors on a laser printer, and then smooth it with an iron to prepare the future board. It remains only to soak the paper with water and pickle the board in the etching solution.

The technology is so good and, it can be said, lazy that even with the manufacture of only one instance, a printed circuit board is made. Although printed circuit boards have no advantages compared to surface mounting, if several copies of the same device are not required.

But, before assembling a printed circuit board, the circuit is most often assembled on a layout. In the simplest case, on a piece of PCB, plywood or thick cardboard, power buses made of tinned wire are fixed at the edges ...

One of my friends turned to me with this request: they say, I want the fireplace to turn on in the garage on a call from a cell phone. He has a workshop there, and it’s cold in the mornings, so he wants to turn on the fireplace two or three hours before arrival. Everything is very simple: he turns on the fireplace by phone, and two hours later, if he does not come, the fireplace will simply turn itself off.

Talk that this is easier to do if you buy a programmable relay did not convince him. Apparently, he might not have appeared there on some days, but this was not amenable to any accounting when programming the relay. And he would spin the counter there while the fireplace was warming an empty room.

Nowadays, there are already many industrial devices that are controlled by the GSM (Global System for Mobile Communication) standard — a digital standard for mobile communications or a now familiar mobile phone. This is a burglar alarm, various control cabinets ...

The article describes the installation sequence of the drywall partition, which significantly reduces the cases of violation of the insulation of the cables laid in it.

In recent years, the popularity of drywall partitions is growing. This is understandable: quickly, efficiently, conveniently. But how to protect the electric cables laid in such a partition, if each square meter of the partition contains up to hundreds of pointed screws (self-tapping screws) that can easily pierce any cable? Laying a cable along a certain route, for example, strictly 20 centimeters from the floor, helps to avoid misunderstandings, but more often this is not enough.

How to lay cables so that not a single screw breaks the insulation when screwing drywall sheets? A standard drywall partition consists of a frame assembled from galvanized steel profiles ...

The electronic constructor is an excellent developing game designed for the popular explanation in an interesting and fascinating form of various physical phenomena and processes.

Be sure to buy an electronic designer is for students in grades 6-11, because it is no secret that for a complete and clear understanding of physics, a school course alone is not enough. Therefore, today schools that use advanced teaching technologies in their educational process use electronic designers as a visual aid in practical classes in physics. And this is understandable, because modern electronic designers have been developed on the basis of the latest achievements of science and technology and have been highly appreciated by teachers.

Electronic designers are made of high-quality environmentally friendly plastic, reliable connecting elements, they use the most modern electronic components ...