To simplify the story, you can imagine a transistor in the form of a variable resistor. The conclusion of the base is just the very handle that you can twist. In this case, the resistance of the collector - emitter section changes. Of course, you don’t need to twist the base, it can come off. But to apply some voltage to it relative to the emitter, of course, is possible.

If the voltage is not applied at all, but simply take and close the conclusions of the base and emitter, even if not short, but through a resistor of several KOhms. It turns out that the base-emitter voltage (Ube) is zero. Consequently, there is no base current. The transistor is closed, the collector current is negligible, just the same initial current. About the same as a diode in the opposite direction! In this case, they say that the transistor is in the OFF position, which in ordinary language means it is closed or locked. The opposite state is called saturation ...

First you need to decide what a warm floor is and why it is needed. The warm floor is not just a device that allows you to walk without shudder on the tiled floor of the bathroom in the early cold morning. This is a room heating system, which in some cases can even be primary, rather than auxiliary.

Moreover, heating a room with underfloor heating has a number of advantages compared to radiator heating. So, heated air near the floor surface retains a feeling of warmth and comfort, and colder in the upper part of the room provides freshness at the required humidity level. In a word, a warm floor is a favorable microclimate in an apartment or a room. There are two options for installing a heated floor in a country house: water and electric underfloor heating. In the article, we will consider in detail the option of installing an electric floor heating ...

The appearance on the market of T5 standard fluorescent lamps marked a new era in the development of gas-discharge light sources. With a small bulb diameter, these lamps have very high efficiency and a long service life. But the main news was their complete incompatibility with existing lighting fixtures. Is such a decision justified in relation to hundreds of millions of luminaires for T8 lamps, and what are the reasons for this approach?

The electrical and structural parameters of T5 lamps are such that it is impossible to ignite or maintain operating parameters using traditional ballast equipment (ballasts). For example, the operating voltage of an 80 W lamp is 152 V, and for a 35 W lamp at a current of 0.175 A, the operating voltage is even equal to 205 V. With a network voltage of 220V, no electromagnetic ballasts can provide such operating parameters - the lamps will inevitably go out ...

Once, thanks to AutoCAD, designers switched from working on computers to computers. However, modern projects are so complex, and their production deadlines are so tight that AutoCAD no longer meets all modern design requirements.

Currently, various computer-aided design systems are actively replacing the "electronic culman", offering to accelerate the implementation of the project, automate routine work, monitor the design process and warn about errors.

AutoCAD Electrical is a well-known AutoCAD for creating projects in the field of electrical engineering, automation, industrial control systems, instrumentation and automation systems and other areas. The program contains a full set of AutoCAD functions, to which specialized tools are added that automate the processes of creating diagrams, layout drawings, report generation, etc.

On the one hand, wiring accessories for a country house are well-known sockets, switches, stationary lamps, frames, socket boxes and the like. But, on the other hand, a country house differs from a template city apartment in that it always has some individual features. Speaking differently, usually at the construction stage, the owner of a house decides what exactly should be in his own house from the electrotechnical benefits, and no one restrains him in this.

The riot of fantasy of the future homeowner is limited only by the size of his wallet. Therefore, in a country house you can often come across some kind of wiring exotic. In addition to the already familiar floor heating and recessed fixtures, a wide variety of sensors, buzzers, surveillance cameras, thermostats and even frequency converters and other complex electronic devices are increasingly being installed ...

At the very end of the previous part of the article, a “discovery” was made. Its meaning is that a small base current controls a large collector current. This is precisely the main property of the transistor, its ability to amplify electrical signals. In order to continue the further narration, it is necessary to understand how large the difference of these currents is, and how this control occurs.

To better remember what is being said, the figure shows an n-p-n transistor with power supplies for the base and collector circuits connected to it. Everything that is told about the transistor of the n-p-n structure is quite true for the p-n-p transistor. Only in this case should the polarity of the power sources be reversed. And in the description itself, “electrons” should be replaced with “holes”, wherever they occur. But at present, transistors of the n-p-n structure are more modern, more in demand ...

A transistor is an active semiconductor device, with the help of which amplification, conversion and generation of electrical oscillations is carried out. Such an application of the transistor can be observed in analogue technology. In addition, transistors are also used in digital technology, where they are used in key mode. But in digital equipment, almost all transistors are “hidden” inside integrated circuits, and in huge quantities and in microscopic dimensions.

Here we will not dwell too much on the electrons, holes and atoms, which were already described in the previous parts of the article, but some of this, if necessary, will still have to be remembered. The transistor consists of two transitions, so the diode can be considered as the precursor of the transistor, or its half. If the p-n junction is at rest ...

It is interesting to trace the origin of the names of market products. For example, the X10 standard owes its name to the mean Scots, who so economically designated their successful, well-known, version of the home automation protocol.

What prompted the Danes to name their standard “Z-Wave” is not exactly known. Either the proximity of the seas, or perhaps the feature of wireless load control, influenced the name of the standard. One way or another, but today he has received strong support in the face of an international consortium of leading world manufacturers and is becoming very popular.

The standard is based on the ideology of building a network (mesh - network) of devices interconnected via a radio channel. But before moving on to a specific discussion of devices running the Z-Wave protocol, we’ll figure out if automation is needed at home, and if so, which one? Any automation at home is, first of all, costs, both material and time for installation of systems ...

One of the most common malfunctions of modern DVD players is poor reading of data from the disc or even a complete lack of reading. There are about a dozen reasons for this problem.One of the first on the list is the loss of the emission of a laser diode, both a CD and a DVD diode. More often than the last.

Hence the selective reading, that is, the device does not read DVD discs, but perfectly “catches” and plays CDs. Or exactly the opposite. As repair practice shows, on average, the head of a DVD player lasts from 3 to 5 years. And every year this figure decreases, as well as the cost of heads.

What to do if your player does not read DVD discs, treacherously signaling “NO DISK” for all your attempts to watch your favorite movie after a hard day? Well, as I said, there can be about a dozen reasons ...

It is necessary to warn right away: there is no mistake in the title, there will be no story about cosmic energy consonant with the name. We will leave it to esotericists and science fiction writers. And we will talk about the usual phenomenon with which we coexist alongside throughout life.

How many people know due to what processes the juices in trees rise to a considerable height? For sequoia, it is more than 100 meters. This transportation of juices to the photosynthesis zone occurs due to the work of the physical effect - osmosis. It consists in a simple phenomenon: in two solutions of different concentrations, placed in a vessel with a semipermeable (permeable only for solvent molecules) membrane, a level difference appears after some time.

And now from wildlife we ​​will return to technology. If sea and fresh water are placed in a vessel with a septum, then due to different concentrations of dissolved salts, osmotic pressure appears and the level of sea water rises ...

The installation procedure for wiring in a country house depends on the type of wiring itself. Hidden or open - the choice of one or another option determines all the technology and all the difficulties that a homeowner will have to go through when electrifying his country residence.

Open wiring, the installation of which is connected with the direct laying of the cable on the walls and ceiling, has long become an anachronism and a thing of the past. If the house is wooden, with a deliberate lack of interior decoration, then such installation is contrary to the rules of fire safety. And in all other cases, an open cable routing openly spoils the interior. The latter applies to open wiring in corrugated and smooth pipes. Therefore, open wiring in country houses is usually performed in plastic cable channels. According to the color of the interior, you can choose the appropriate box ...

Internal wiring in country houses is most often performed open. Since the interior decoration in these houses usually includes decorative elements and natural wood paneling, the most typical route for laying the cable is a plastic cable channel. After all, the open installation of cable lines on combustible surfaces is prohibited by the applicable PUE standards. At the same time, open cable laying in pipes or corrugated pipes on clips is rejected for aesthetic reasons.

Regarding the choice of cable products for wiring in a country house, we can say that it is not particularly wide. In order not to have any problems afterwards, it is better to stop on VVG-ng copper cables (for those who want to save a little), or NYM (for those who are not limited in funds). The chains of sockets are traditionally made with a cable with three conductors with a cross section of 2.5 square meters. mm., and the lighting circuit ...