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Various electronic devices. Schemes, articles, descriptions

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Types and characteristics of solar panels

Section Alternative energy sources. The solar battery consists of individual elements connected in series-parallel (Fig. 1.3, 1.4). The elements are used in portable electronic devices, for miniature lamps (LEDs) and cell phone chargers. The prototype of modern solar cells are photomultipliers (PMT) ... >>


Section Beginner radio amateur. A trigger is a serial type device with two stable equilibrium states, designed to record and store information. Under the action of input signals, the trigger can switch from one stable state to another. In this case, the voltage at its output changes abruptly. As a rule, the flip-flop has two outputs: direct and inverse. The number of inputs depends on the structure and functions performed by the trigger. According to the method of recording information, triggers are divided into asynchronous and synchronized (clocked). In asynchronous triggers, information can be recorded continuously and is determined by the information signals acting on the inputs at a given time. If information is entered into the trigger only at the time of the action of the so-called clock signal, then such a trigger is called synchronized or clocked. In addition to information inputs, clocked triggers have a clock input, a synchronization input ... >>

Single stage AF amplifier

Section Transistor power amplifiers. Single stage AF amplifier. This is the simplest design that allows you to demonstrate the amplifying capabilities of a transistor. True, the voltage gain is small - it does not exceed 6, so the scope of such a device is limited. Nevertheless, it can be connected to, say, a detector radio receiver (it must be loaded with a 10 kΩ resistor) and, using the BF1 headphone, listen to the transmission of a local radio station ... >>

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Articles on various electronic devices

Articles on various electronic devices; schemes of various electronic devices; descriptions of various electronic devices: 12 articles



Latest news of science and technology, new electronics:

The speech of sperm whales is similar to that of humans 18.05.2024

In the world of the ocean, where the mysterious and unknown coexists with the studied, sperm whales, with their huge brains, are of particular interest to science. Researchers, working with a huge array of audio recordings collected during the Dominica Sperm Whale Project (DSWP) - more than 8000 recordings, seek to unravel the secrets of their communication and understand the structure and complexity of the language of these mysterious creatures. By studying in detail the recordings of 60 sperm whales in the eastern Caribbean, scientists have revealed surprising features of their communication, revealing the complexity of their language. "Our observations indicate that these whales have a highly developed combinatorial communication system, including rubato and ornaments, which indicates their ability to quickly adapt and vary during communication. Despite significant differences in evolution, sperm whales have elements in their communication that are characteristic of human communication," says Shane Gero, a biologist at Carleton University and director of the CETI project. Issl ... >>

Electron spin for quantum information transfer 18.05.2024

The transfer of quantum information remains one of the key tasks of modern science. Recent advances in the use of electron spin to expand the capabilities of information transfer in quantum systems have become very important. Researchers at Lawrence Berkeley National Laboratory are pushing the frontiers of quantum information science by experimenting with the possibilities of electron spin. Electron spin, a natural quantum bit, is a potentially powerful means for storing and transmitting information in quantum systems. Magnon wave packets, collective excitations of electron spin, have revealed their potential to transmit quantum information over significant distances. The work of Berkeley Lab researchers has revolutionized the way such excitations propagate in antiferromagnets, opening up new prospects for quantum technologies. Using pairs of laser pulses, scientists disrupted antiferromagnetic order in one place and simultaneously studied it in another, creating ... >>

Sound-absorbing silk 17.05.2024

In a world where noise is becoming increasingly intrusive, the emergence of innovative materials that can reduce its impact is of great interest. MIT researchers have unveiled a new sound-absorbing silk fabric that promises to revolutionize quiet spaces. The Massachusetts Institute of Technology (MIT) has made significant breakthroughs in the field of sound absorption. Researchers have developed a special silk fabric that can effectively absorb sound and create cozy, quiet environments. The fabric, thinner than a human hair, contains a unique vibrating fiber that is activated when voltage is applied to it. This feature allows the fabric to be used to suppress sound waves in two different ways. The first method uses fabric vibrations to generate sound waves that cover and cancel out unwanted noise, similar to noise-canceling headphones. This p ... >>

Random news from the Archive

Brain rhythms and learning 02.03.2015

It is known that the activity of brain neurons develops into waves or rhythms that can be seen on an electroencephalogram: alpha rhythm, beta rhythm, gamma rhythm, and others. Rhythms replace each other depending on what exactly the person is doing at the moment. For example, alpha waves appear during rest, when we are not busy with anything, but we are not sleeping either; delta waves correspond to deep dreamless sleep; if attention is focused on some task, then this can be seen from the fast theta and gamma rhythms. Moreover, different areas of the brain can generate different waves because they perform different tasks. By observing the dynamics of rhythms, one can say a lot about how the "departments" of the brain communicate with each other and how responsibilities are distributed in solving cognitive tasks related to memory, attention, etc.

In a paper published in Nature Neuroscience, Earl Miller and Scott Brincat of the Massachusetts Institute of Technology describe the changes in brain wave activity that accompany memory and learning. Researchers were not interested in memory in general, but in its form, which is called explicit: it is responsible, for example, for the connection between objects, events, etc. We associate a person’s appearance with his name, but a certain event with the place where it happened, as times thanks to explicit memory. It is formed with active conscious efforts on the part of the individual, and it exists not only in humans, but also in animals.

In the experiment, the monkeys were shown pairs of pictures, so strong links had to be established between some of the pictures. The monkeys learned by trial and error: they were shown pictures over and over again, and they had to guess whether they were related or not. If the animal correctly guessed that the depicted objects were related to each other, it was given a treat. Simultaneously, the researchers recorded activity in the hippocampus and prefrontal cortex, two areas of the brain that play a key role in learning. It turned out that the frequency of the waves in them changed depending on whether the monkey gave the correct or incorrect answer. If the result corresponded to the expectation, then a beta rhythm appeared with a frequency of 9-16 Hz. If the answer was wrong, then the frequency dropped to 2-6 Hz, which corresponded to the theta rhythm.

Memorization is associated with the formation of new neural circuits: synaptic connections between neurons maintain the "memory cell" in working order. It was previously shown that the strength of synapses (that is, their strength and efficiency) depends on the rhythm in which nerve cells have to work: if beta frequencies increase intercellular contacts, then theta frequencies, on the contrary, weaken them. Together with the new results, we can imagine the following model: the correct answer stimulates beta activity in the brain, which, in turn, strengthens the formed neural circuits - after all, they remember everything correctly. If not, then theta activity will invalidate the wrong memory.

This is not the first work on the relationship between brain waves and memory. So, last year, Nobel laureate Suzumi Tonegawa published an article with colleagues that discussed similar things - how the brain corrects memory if it sees an incorrect result. Those experiments were done on mice and focused on the hippocampus and the entorhinal cortex (another well-known memory center). Then neuroscientists discovered that gamma-rhythms serve as a signal for correcting information, synchronizing the work of two areas of the brain.

Of course, the process of memorization is too complex to be reduced simply to the alternation of several types of waves. By changes in electrical rhythms, we can judge the behavior of fairly large ensembles of cells and entire sections of the brain at the moment when an individual needs to remember some new information. Why one type of rhythm replaces another, what mechanism links such a replacement with correct or incorrect memory, researchers have yet to find out. Although it is possible that in the future we will have memory stimulants that will help the brain switch to the right rhythm when we need to remember something.

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