Personal safety. Schemes, articles of the Free Technical Library

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Personal safety. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

Personal safety

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Power supply with quenching capacitor, 220/3 volts 0,5 amps

Section Power supplies. The use of capacitors to step down the voltage supplied to the load from the lighting network has a long history. In the 50s, radio amateurs widely used capacitors in transformerless power supplies for radio receivers, which were connected in series to the filament circuit of radio tubes. This made it possible to eliminate the quenching resistor, which is a source of heat and heating of the entire structure. Recently, there has been a return of interest in power supplies with a quenching capacitor. The disadvantage inherent in all such devices without exception - increased danger due to the galvanic connection of the output with the electrical network - is clearly recognized, but allowed based on the literacy and accuracy of the user. However, these deterrents are not enough to keep out of trouble, which is why transformerless devices can have only very limited use. ... >>

Oscillators with stable amplitude

Section for radio amateur-designer. The harmonic signal generator (Fig. 1) with frequencies from 10 Hz to 100 kHz has a high amplitude stability. The stabilization of the signal amplitude is carried out using a field-effect transistor included in the PIC circuit. The field effect transistor is controlled by a constant voltage, which is formed on the capacitor C1 and amplified by the op-amp DA2. The large transfer coefficient of the op amp DA2 holds the amplitude of the harmonic signal with an accuracy of tens of millivolts in the range from 1 to 9 V. The amplitude is adjusted by the potentiometer R9. Output harmonic distortion less than 0,1% ... >>

Expanding the possibilities of a dynamic lighting installation

Section Color and Music Settings. The refinement described below can be carried out with any automatic light-dynamic installation (SDU), the power amplification unit of which is assembled according to the traditional scheme - channel trinistors with series-connected screen device lamps are connected in parallel to the diagonal of a diode bridge powered directly from the mains. The modification concerns the power amplification unit, in which six diodes VD5-VD10 are added (see diagram), an additional lamp (EL4 - EL9) of the screen is connected in series with each diode. We will consider the operation of the block on the upper pair of channels according to the scheme ... >>

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Articles on personal safety

Articles on personal security; schemes of devices for personal safety; descriptions of devices for personal safety: 7 articles

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Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive

Samsung SUHD TVs 15.01.2015

Samsung Electronics introduced TVs called SUHD. The announcement included models with screen sizes from 48 to 88 inches, divided into the JS9500, JS9000 and JS8500 series. The manufacturer did not begin to decipher the abbreviation SUHD. Foreign publications believe that it means "Samsung Ultra High Definition" or "Superior Ultra High Definition" (i.e., higher quality UHD).

The panels of the new TVs use "quantum dots" or nanocrystals, as Samsung itself calls them, special particles whose size affects the wavelength of transmitted light and, thus, the color of the pixel. The company claims that this technology allows, firstly, more light to pass through the matrix (i.e., get a brighter image), and secondly, to get a purer color cast compared to modern TVs.

Samsung says SUHD is capable of offering 64 times the color reproduction of conventional TVs and 2,5 times the brightness. The company did not specify with which TVs the comparison was made. Foreign publications write that the SUHD color range is as close as possible to OLED at a cost that is several times lower.

"Quantum dots promise to solve a fundamental problem with modern LCD TVs, which have inferior color reproduction to plasma and OLED," explains The Verge. passing through the matrix. This allows you to significantly expand the color range, and do it for a third of the cost of an OLED panel."

Previously, nanoparticles (or quantum dots) have already been used in consumer electronics: the Amazon Kindle Fire HDX tablet and the Asus Zenboox NX500 laptop. There were also suggestions that such technology will be equipped with the Apple iPhone 6, but they were not confirmed. Quantum dots are produced in the form of powders and films, there are several manufacturers of this material, for example, Nanoco Technologies.

The new Samsung TVs have one more feature: they will all be based on Tizen. It is an operating system with an open Linux kernel. Recently, its prospects have become vague - Samsung, which is developing it together with Intel, several times postponed the launch of a smartphone based on Tizen, first in Russia, then in India (the device was never released).

Now Samsung has decided to make Tizen the basis of smart TVs. Foreign media draw parallels with WebOS, which was bought for similar purposes by LG Electronics, Samsung's main competitor in the TV market. Samsung promises to completely rework the Tizen shell in its new models and borrow control features from mobile devices to make it easier for the user to communicate with the TV. In addition, Tizen will expand the choice of applications and, thanks to the openness of the platform, ensure compatibility with a much larger number of home devices, according to the company.

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