One of the legends of electronics is the NE555 integrated timer chip. It was developed back in 1972, so now in the last 2012, it turned exactly 40 years old. Such longevity is far from every chip and not even every transistor can be proud of. So what is so special about this microcircuit, which has three fives in its marking?

Signetics launched the serial production of NE555 exactly one year after it was developed by Hans R. Kamensind. The most amazing thing in this story was that at that time Kamensind was practically unemployed: he quit PR Mallory, but did not manage to get anywhere. In fact, it was a “homework”.

The chip saw the light of the day and gained so much fame and popularity thanks to the efforts of Signetics manager Art Fury. The most interesting thing is that the microcircuit has not lost its relevance to this day ...

Pure semiconductors have the same amount of free electrons and holes. Such semiconductors are not used for the manufacture of semiconductor devices, as was mentioned in the previous part of the article.

For the production of transistors (in this case, they also mean diodes, microcircuits, and actually all semiconductor devices), n and p types of semiconductors are used: with electronic and hole conductivity. In n-type semiconductors, electrons are the main charge carriers, and holes in p-type semiconductors.

Semiconductors with the required type of conductivity are obtained by doping (adding impurities) to pure semiconductors. The amount of these impurities is small, but the properties of the semiconductor change beyond recognition. Transistors would not be transistors if they were not used in their production ...

Let's start with the simplest. Suppose we have a residential building (cottage) which is powered by a power line (overhead line) and in which metal communications (gas, water supply, etc.) are not connected. We list the dangers that may await us in this case and then how to deal with them.

In case No. 1, a direct lightning strike can destroy the building itself, cause a fire in it, damage the electrical equipment of the house and electrical appliances included in the outlets. In this case, there is only one protective measure - the installation of external lightning protection on the house.

In case No. 2, the TV will fail, possibly igniting it. Protection measures: - installation of the antenna in the external lightning protection zone and / or disconnect the antenna cable from the TV. In case No. 3, a surge voltage of tens of kilovolts is brought into the house, which will cause damage to the electrical wiring insulation and damage to electrical appliances connected to outlets. Protection measures: turn off the power at the entrance to the house at the time of departure ...

The article is devoted to metal halide lamps, the features of their design, operation and application.

Encountering the term “metal halide lamp”, most people have associations with an incandescent lamp, its variant with a halogen cycle. Now this is the most common misconception. Especially when, after the protests of chemists, they changed the already established name “metal halide” to “metal halide”. Without going into linguistic disputes, we agree that we will talk about one of the representatives of discharge lamps.

This representative is rather capricious, expensive and dangerous. Nevertheless, for more than four decades, such light sources have been produced in a wide assortment by leading lighting companies.The annual production of metal halide lamps by OSRAM alone is more than 10 million units. If we add the products of General Electric and Philips to this amount ...

A talented Russian engineer and inventor Mikhail Osipovich Dolivo-Dobrovolsky is considered one of the founders of the technique of applying alternating currents. His name is associated with work in the field of creating the technique of three-phase alternating currents. He is the creator of a simple and reliable asynchronous motor to use. An engine of this design is used today. All elements of the three-phase system were created by Dolivo-Dobrovolsky.

Mikhail Osipovich was born on January 2, 1862 in the family of an official. He became the firstborn in a large family Dolivo-Dobrovolsky, who at that time lived in the city of Gatchina. In 1873, the Dolivo-Dobrovolsky family moved to Odessa, where the childhood and youth of the future talented inventor passed. There, in Odessa, he brilliantly graduated from the Odessa Real School. Then he entered the Riga Polytechnic Institute. But Mikhail Osipovich did not have time to finish it ...

Rest in a house outside the city becomes comfortable and brings pleasure only when the tasks of maintaining the house and the plot are minimized. Often, the owners are forced to irrigate landings, control the provision of ventilation and heating at home, turn on the lighting of the site, etc.

Today, this much-needed functionality can be completely delegated, at the same time, not to hired workers, but to modern multifunctional modular electrical equipment that allows you to perform all the processes on a suburban area in automatic mode, i.e. without human intervention. Its installation is quick and easy in existing power supply systems and, thus, there is no need for complex repair work. There can be many processes, but in this article we will focus on the automatic inclusion of street lighting when darkness falls ...

For power engineers of enterprises and large shopping centers, there is no doubt that reactive energy exists. The monthly bills and the very real money that goes to pay for reactive electricity convinces of the reality of its existence. But some electrical engineers seriously, with mathematical calculations, prove that this type of electricity is fiction, that the separation of electric energy into active and reactive components is artificial.

Let's try and we will sort this issue out, especially since the creators of “unique” and “revolutionary” energy-saving devices speculate on not knowing the differences between different types of electricity. Promising huge percentages of energy savings, they knowingly or unknowingly replace one form of electrical energy with another. Let's start with the concepts of active and reactive electricity. Without going into the wilds of the formulas of electrical engineering, you can determine ...

In terms of everything that was said above, the most reasonable and least expensive is the manufacture of a transformer power supply. A suitable ready-made transformer for powering semiconductor structures can be selected from old tape recorders, tube televisions, three-program loudspeakers and other obsolete equipment. Ready-made network transformers are sold in radio markets and in online stores. You can always find the right option.

Externally, the transformer is a W-shaped core made of sheets of special transformer steel.On the core is a plastic or cardboard frame on which the windings are located. The plates are usually varnished so that there is no electrical contact between them. In this way they fight eddy currents or Foucault currents. These currents just warm the core, it's just a loss. For the same purposes, transformer iron is made ...

Electronic devices can be divided into two groups: mobile and stationary. The first of them use the so-called primary power sources, - galvanic batteries or accumulators that have a supply of electricity.

It immediately recalls mobile phones, cameras, remote controls and many other portable devices. In this case, rechargeable batteries and batteries are beyond competition, since there is simply nothing to replace them with. The only inconvenience, the cost of mobility is that the duration of such devices is limited by the capacity of the batteries, and, as a rule, is small. An exception to this rule are, perhaps, watches. Their energy consumption is very low, which is incorporated at the design stage, so the clock can go on a single battery for a whole year, or even more. Stationary devices, as a rule, receive power from secondary sources ...

The article considers the advantages and disadvantages of incandescent lamps and the problems that arise when replacing them with modern light sources.

So, the brainchild of the brilliant Thomas Edison leaves us. For almost a century, incandescent lamps reigned supreme in the field of artificial lighting. From super-miniature flashing lights to powerful floodlights. Such were the possessions of this simple, reliable light source, which has not undergone major changes since the invention. But time passes, and the market is filled with various types of discharge lamps, LED light sources are constantly knocking on the door.

Despite a century of improvement, it was not possible to overcome the main disadvantages of incandescent lamps: low efficiency (less than 4%) and short service life. Sophisticated attempts to increase efficiency led to the development of halogen lamps, but they could not qualitatively change the situation ...

The most popular material for the construction of country houses was and remains a tree. Which, with all its numerous advantages, has one serious drawback, is, as firemen say, "combustible material."

Fire statistics indicate that more than half of fires in wooden houses occur due to faulty wiring. In practice, the main cause of malfunctions and the subsequent short circuit is most often a violation of the integrity of the insulation of the wires in the wiring. As a rule, this occurs either due to the increased load on the wires or due to mechanical damage to the insulation.

Why is this happening? Most homegrown "jack-of-all-trades", in order to save time, effort and money, lay hidden electrical wiring on wooden bases, boldly hiding it behind the ceiling sheathing, under the wall cladding, baseboards, in the voids of ceilings and pushing the "unreasonable" client .. .

In electrical engineering, various materials are used. The electrical properties of substances are determined by the number of electrons in the outer valence orbit. The fewer electrons are in this orbit, the weaker they are associated with the nucleus, the easier they can go to travel.

Under the influence of temperature fluctuations, the electrons break away from the atom and move in the interatomic space. Such electrons are called free, and they create an electric current in the conductors. Is there a large interatomic space, is there room for free electrons to travel inside matter?

The structure of solids and liquids seems continuous and dense, reminiscent in structure of a ball of thread. But in fact, even solids are more like a fishing or volleyball net. At the household level, this certainly cannot be discerned, but it has been established by accurate scientific research ...