To better understand the principles of constructing circuits using operational amplifiers, they often use the concept of an ideal operational amplifier. What is its ideality, its wonderful properties? There are not so many of them, but they all tend either to zero, or even to infinity. But this is how an operational amplifier behaves that is not covered by feedback (OS) and generally does not have any external connections.

In this article we will try to talk about feedback and some schemes for including operational amplifiers without mentioning cumbersome mathematical formulas with integrals. But some, quite simple and understandable, at the level of the eighth grade of the school, which will help to understand the general meaning, still can not be avoided.

With such a "rampant" gain, it is enough to apply only a few microvolts to its inputs (for example, mains interference) to get a voltage close to the output ...

First, a few words about what operational amplifiers (op amps) are. The name itself suggests that some operations are performed with their help. Could it be a surgical instrument? Not at all. This tool is designed to perform various mathematical operations. Initially, operational amplifiers were used in analog computers (AVMs), in which information was represented by continuous signals in the form of currents and voltages.

Although AVMs are now a thing of the past, analog signals received from various sensors (for example, fluid pressure or the angle of rotation of the gas pedal) are still used very widely. And there’s simply nowhere to go from this. Most often, analog signals are converted to digital using, for example, an ADC, and their further processing is performed digitally using microprocessors or microcontrollers ...

Electrical and magnetic phenomena have been studied for a long time, but it never occurred to anyone to somehow relate these studies to each other. And only in 1820 it was discovered that a current conductor acts on the compass needle. This discovery belonged to Danish physicist Hans Christian Oersted. Subsequently, the unit of measurement of the magnetic field strength in the GHS system was named after him: the Russian designation E (Oersted), the English designation Oe. The magnetic field has such intensity in a vacuum during induction of 1 Gauss.

This discovery suggested that a magnetic field could be obtained from an electric current. But at the same time, thoughts arose about the inverse transformation, namely, how to get an electric current from a magnetic field. Indeed, many processes in nature are reversible: ice is obtained from water, which can again be melted into water ...

After the story about the use of capacitors, it would be logical to talk about another representative of passive radio elements - inductors. But the story about them will have to start from afar, to remember the existence of a magnetic field, because it is the magnetic field that surrounds and penetrates the coils, it is in a magnetic field, most often alternating, that the coils work. In short, this is their habitat.

Magnetism is one of the most important properties of matter, as well as, for example, mass or electric field. The phenomena of magnetism, however, like electricity, have been known for a long time, only then science could not explain the essence of these phenomena. An incomprehensible phenomenon was called "magnetism" by the name of the city of Magnesia, which was once in Asia Minor.It was from ore mined nearby that permanent magnets were obtained. If it was promised to talk about inductors, then we will talk about electromagnetism ...

Summer residents and owners of suburban housing, in which the power supply is low, often encounter a problem that arises during the installation and operation of the electric hot water supply system at home.

Turning on a powerful submersible pump of an automatic pumping station with a running water heater leads to an overload of the power supply and tripping of a circuit breaker located in the shield near the electricity meter.

The reasons for this are clear, since the starting current of the electric motor can exceed its operating current by 2 to 3 times. And if silt or sand gets on the impeller of the pump, then not only the starting current increases, but also the working current. When the inrush current occurs when other energy-intensive consumers are connected to the power grid, this is enough to trigger the machine. After all, for example, a storage water heater installed in private homes...

Safety during electrical work must always be extremely responsible. When performing construction work, injuries often result from improper use of various tools and electric shock.

Construction companies, as a rule, provide on-the-job training on safe working methods. Data on the conducted briefings shall be reflected in the safety journal indicating the numbers of the instructions for which the briefing was conducted.

Unfortunately injuries do happen. And when an investigation is carried out about an injury that has occurred, the injured person very often says that he was not instructed on safety issues: “Yes, I signed it in some kind of magazine somewhere, but I don’t know why.” Therefore, it is necessary not only to instruct, but also to give all the required instructions for personal use to all the workers for signature ...

In conversations with customers, when discussing 12-volt halogen lighting, for some reason the word "low current" often flickers, which characterizes the corresponding attitude to the choice of wires - which is at hand, then we use it, the voltage is safe.

The voltage of 12 volts is really safe, in the sense that touching the bare wire with such voltage is simply not felt, but the currents in such circuits flow quite large.

Consider, for example, the power supply of a standard halogen lamp with a power of 50 W, the current in the primary circuit of the transformer I = 50W / 220V = 0.23A (or, more precisely, a little more, taking into account the efficiency of the transformer), while the current I = 50W / flows in the secondary circuit of 12 V 12V = 4.2 A, which is already 18 times more. If you do not take this fact into account, you may encounter very unpleasant surprises ...

In the electrotechnical literature, in the descriptions of the material of the conductive conductors of electric wires and cables, you can find the phrase: alumina conductor. What kind of material is aluminum-copper?

The information offered on the Internet on this issue is very scarce. But even in the electrotechnical GOSTs of the eighties (during the former USSR), along with copper and aluminum, another conductive material was necessarily present - aluminum-copper. This suggests that in pre-perestroika Russia, aluminum-copper was considered a promising technical find.

Indeed, aluminum-copper has some advantages that make this material attractive for use in everyday life and industry.But first, a brief look at some of the user-defined features ...