Note to the student. Schemes, articles of the Free Technical Library

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Note to the student. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

Note to the student

We recommend reading in our Free Technical Library:

Antenna matching with feeder

HF Antenna Section. This question interests many radio amateurs. It occurs, for example, when it is necessary to connect a symmetrical two-wire 300-ohm feed line to the antenna instead of a 75-ohm coaxial cable or, conversely, when replacing a 300-ohm open line with a 75-ohm coaxial one. The feeder can not always be directly connected to the antenna, bypassing the matching device. The issue of performing a compensated transition (or matching device) from the antenna system to the feeder line is one of the main ones in the design of antennas. It is mainly aimed at reducing losses in the feeder by providing a regime in it close to that of a traveling wave. The main feeder line is usually the longest. Therefore, it is desirable to coordinate it better with the load ... >>

Diode radio receiver 65...130 MHz

Section Radio reception. The receiver is a simple diode mixer. The reception frequency is determined by the GSS frequency. It can be used as a wavemeter, single-sideband or telegraph radio receiver. It all depends on your imagination ... >>

Voltage stabilizer, short-circuit protected output, 21/2-12 volts 0,3 amps

Section Voltage stabilizers. The figure shows a diagram of a transient parametric stabilizer based on a composite control transistor T2, T3 with an output short-circuit protection device on transistor T1. The rated input voltage of this stabilizer is 21 V, the load current is 0,3 A, the output voltage range is 2...12 V. The protection device operates as follows. A stable bias voltage of about 1 V is supplied to the base of transistor T1,7 from diodes D1 and D2 (used as stabistors) ... >>

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Articles for the student

Articles for the student; schemes for the student; descriptions for the student: 14 articles

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

Artificial leather for astronauts 14.12.2018

The European Space Agency (ESA) has started working on 3D printing technology for artificial skin and organs for astronauts.

Astronauts of the Apollo lunar mission made their 12-day flight with a modest first aid kit, which contained only bandages, antibiotics and aspirin. Future space travelers who will spend months and even years away from Earth will need more advanced medical support.

That is why ESA is launching a large-scale scientific project called "3D printing of living tissue for space exploration." Several European universities will work on it. The project aims to explore the prospects for using 3D bioprinting as a medical aid during long-duration space flights and stays on Martian or lunar bases.

“In the event of an urgent medical problem, a quick return home will not be possible. Patients will have to be treated on the spot,” emphasizes Sandra Podhajski, head of the project.

For example, in the event of a severe burn, it is theoretically possible to grow new skin from the patient's own cells and then transplant it.

Just as standard 3D printers use polymers or metals to print three-dimensional objects, 3D bioprinters use human cell-based "bio-inks" as well as nutrients and special scaffolds needed to build the correct structure of skin, bone or cartilage tissue. . In the next decade, scientists hope to be able to print entire organs.

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