The need to transfer sockets and switches, as a rule, arises after moving furniture in the apartment, or when bringing the wiring to the so-called European standard, according to which the sockets are installed at a height of 20 - 30 centimeters, and switches at a height of 90 - 120 centimeters from the floor.

If you want to lower the outlet, and the wiring is done in a coupler, then just install the new installation box in the desired location and shorten the cable to the desired length. The situation is more complicated when you need to increase the cable. Two tasks immediately arise here. How to connect cable cores so that the connection is high-quality and durable, and what to do with the old installation box.

The worst solution to this issue is to connect the cable, for example, twisting the cores, insulating the twist, cover the wires with alabaster in the old installation box and forget where this time bomb is ...

Sometimes lighting engineering presents surprises: an unsuccessful light source gains so much popularity that leading lighting companies are engaged in its mass production. It is a question of lamps of arc mercury-tungsten (DRV).

Structurally, a mercury-tungsten lamp is a discharge mercury burner similar to DRL lamps. But in addition, a tungsten spiral is mounted in series with the burner in the bulb. It is located in an external flask, in an argon atmosphere, and serves as a current-limiting element for the burner. Such a lamp does not require external ballast equipment (PRA) and can be directly installed in the lamp instead of incandescent lamps. It was this opportunity that led to the commercial success of DRV lamps. The point here is not only the poverty of enterprises in the CIS countries - the demand for this type of lamp is very high ...

Magnetic starters, as the name implies, were conceived as a switching device for starting electric motors. Therefore, the number of power poles of these devices is almost always equal to three - in terms of the number of network phases. Starters are often equipped with thermal overload relays and a housing with “start” and “stop” buttons.

But the starter turned out to be a very convenient and functional thing. A wide range of rated currents, small dimensions and the possibility of autonomous installation outside of any switchgear or switchboard have led to the fact that magnetic starters have been widely used in everyday life for connecting various powerful electric receivers, for example, heating boilers, to the network.

Like any other electrical device, the magnetic starter periodically also needs repair and maintenance. The magnetic starter maintenance program is simple and includes ...

Recently, there has been constant debate about the form in which a book is more convenient - in electronic or paper. Advocates of technological progress have previously written off paper books to the dustbin of history, and lovers of paper literature do not want to hear about any electronic publications. In fact, any extreme opinion on this issue will be wrong. Truth, as usual, lies somewhere in between.

Technological progress is relentless and necessary. The main advantages of e-books are that they do not require a separate place for storage, are convenient to use (they can be read on a computer, tablet, phone, etc.). Easily assemble and store the whole library in a portable device. In addition, e-books are very cheap! So an e-book usually costs 3-5 times cheaper than a paper counterpart. In this article - a small selection with new licensed e-books from LitRes on the topics "Electronics", "Electronic Constructions and DIY"...

To begin with, the OEL-820 power load optimizer is the newest type of device familiar to experts - a non-priority load disconnect relay, and the only one in the world designed for domestic use. Therefore, we will consider the traditional and new device, as a group of devices that solve the same problem.

For different manufacturers, these devices are also called: priority relay, non-priority load relay, priority load relay, etc.

Priority switchboards help in a situation when, when several energy-intensive consumers are turned on, the total power consumed by them exceeds the limit of allowed power. Priority switchboards are installed at the input to the electrical panel. Their principle of operation is to continuously monitor the power consumed by all consumers used ...

In industrial power supply, the term is used in the form of a simple abbreviation: ABP. Automatic input of power reserve is possible if there is an additional, backup source of power supply. In fact, such a backup source most often becomes an additional backup line, generator or battery installation. Automatic transition to backup power is carried out using relays or special electronic units.

But for a household network, such things seem superfluous: relays, electronic components, a backup line, a generator set ... It's cheaper and easier to sit without electricity, or in the light of a flickering lamp that suffers from unstable or undervoltage. However, it should be remembered that the household network of an apartment or private house in the vast majority of cases is single-phase. And the power line is almost always three-phase ...

The most common use of capacitors is the connection between individual transistor stages, as shown in Figure 1. In this case, the capacitors are called transient.

Transient capacitors pass the amplified signal and prevent the passage of direct current. When the power is turned on, the capacitor C2 is charged to the voltage at the collector of the transistor VT1, after which the passage of direct current becomes impossible. But the alternating current (amplified signal) makes the capacitor charge and discharge, i.e. passes through the capacitor to the next cascade.

Often in transistor circuits, at least in the audio range, electrolytic capacitors are used as transient ones. The rated values ​​of the capacitors are chosen so that the amplified signal passes without much attenuation ...

In previous articles, we briefly talked about the operation of capacitors in AC circuits, how and why capacitors pass AC current. In this case, the capacitors do not heat up, power is not allocated to them: in one half-wave of the sinusoid, the capacitor charges, and in the other, it naturally discharges, while transferring the stored energy back to the current source.

This method of passing current allows you to call the capacitor a free resistance, and that is why the capacitor connected to the outlet does not make the counter spin. And all this is because the current in the capacitor is ahead of exactly 1/4 of the time the voltage applied to it.

But this phase advance allows not only “tricking” the counter, but also makes it possible to create various circuits, for example, generators of sinusoidal and rectangular signals, time delays and various frequency filters ...