Menu English Ukrainian russian Home

Free technical library for hobbyists and professionals Free technical library


Computer modding. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

Computer modding

We recommend reading in our Free Technical Library:

Small-sized antennas for portable MW communication stations (part 2)



HF Antenna Section. In portable and mobile CB radios, antennas with a length of 30 ... 100 cm for portable and up to 1,5 meters for mobile radios are used. Having calculated the input resistance of the active parts of such short pins for a frequency of 27 MHz, we obtain values ​​from 0,5 Ohm for 30 cm to 10 Ohm for 1,5 m. Of course, it is unreasonable to connect such short pins to the output stage of the transmitter without appropriate coordination. Firstly, the efficiency of such a pin as an antenna is low, and secondly, matching the low resistance of the pin with the output stage of the transmitter is very difficult. The most rational solution that came to solving this problem was that the pin is part of a complex system, which is a shortened antenna. Hereinafter, the efficiency of the pin in such a system is considered. ... >>

Tester for Ni-Cd and Ni-MH AA batteries



Section Measuring technology. An unpleasant situation happens when, when going out into nature with a camera, it turns out that recently charged batteries run down very quickly. This can be avoided if they are tested in advance by determining the capacity. Check the batteries will help the device offered to the attention of readers. Its peculiarity is that the test results are displayed on the LCD indicator from the cell phone. The tester is designed to simultaneously test four Ni-Cd or Ni-MH batteries with a nominal voltage of 1,2 V. It can be used to select batteries with similar parameters to make up a battery, train newly purchased batteries, or other preventive actions where they are needed. discharging with safe current. Each battery has a separate discharge indicator. The principle of operation of the device is simple - by discharging the battery through a known resistance to a voltage of 1 V, the discharge time is controlled. The results obtained are displayed on an alphanumeric LCD indicator ... >>

Adaptation of imported phones



Section Telephony. In RL N6 / 92, in the recommendations of P. Mikhailov under the heading How to adapt an imported telephone, it was said about protecting foreign handsets from current surges in domestic telephone lines - using a pair of resistors connected between the socket and the device. However, in my opinion, the author of this recommendation is not entirely correct in stating that sissy tubes fail due to overcurrent. They refuse from voltage overload, because when dialing a number, the transistors in the phone are locked for the period of a currentless pulse, there is no voltage drop in the line, and the full voltage of the PBX line appears between the collector and emitter of closed transistors - more than sixty volts! And imported sissies are designed, as you know, for 48 volts ... >>

To any article in this section and all Encyclopedias you can leave your comment.

Articles on computer modding

Articles on computer moding; computer modding schemes; descriptions of computer modding: 20 articles

 


 

All articles on computers

 


 

Latest news of science and technology, new electronics:

Blinking of the magician and his audience 19.05.2024

Magic and illusions have always captured the attention of the public, but what happens behind the scenes of the magician and in the brains of his audience? Scientists from the UK decided to solve this mystery by conducting a new study involving ten illusionists of varying experience. Illusionists, some of whom had been practicing magic for more than half a century, others for only six months, were invited to demonstrate the same trick - the popular coin trick. Recordings of their performances during training and on stage showed that each of them began to blink significantly more often at the moment of performing the trick. The study's findings indicate that magicians' blink rate may be related to unconscious aspects of their performance. At the same time, as scientists have found, spectators also begin to blink more often, following the movements of the illusionist. This observation supports the idea that magicians may be catalysts for blinking in audiences. Additional research has shown that magicians blink more often during ... >>

Ultrasonic coffee machine 19.05.2024

Iced coffee has become an integral part of coffee culture in recent years. Therefore, engineers from the University of New South Wales decided to improve its preparation. They have developed an ultrasonic coffee machine that reduces the cold brew time for ground coffee beans from 12-24 hours to significantly less time. Iced coffee, or "Cold brew", is popular due to its smoothness, low acidity and low bitterness. It is prepared by steeping ground coffee in cold water for a long time. Unlike traditional hot brewing, which often imparts bitterness to coffee, cold brewing extracts more delicate and complex flavors from the coffee beans. The innovative system, presented by a team of engineers, introduces ultrasonic technology into the coffee preparation process. The system uses ultrasonic waves to speed up the process of extracting oils, flavor and aroma from ground coffee. This allows you to significantly reduce the time ... >>

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 ... >>

Random news from the Archive

Plant Census of China 08.09.2006

The publication of the multi-volume work of Chinese botanists, begun in the 30s, has been completed. Four generations of scientists with a break for the "proletarian cultural revolution" (1966-1976) worked on 126 volumes, which list and describe 31141 species of higher plants known in China.

Local and imported, wild and cultivated, weeds and useful plants are taken into account. Moreover, more than 20 descriptions are illustrated with drawings and photographs. Exceed China in the diversity of flora only Brazil and Colombia.

The poorest area for plants (except for deserts) is the islands in the south of the Indian Ocean, near Antarctica, where there are only 35 species.

Other interesting news:

▪ Mobile phone embedded in teeth

▪ mobile phone fast charging technology

▪ Boat jet engine on outboard water

▪ wine allergy

▪ Brain love for boundaries

News feed of science and technology, new electronics

 

Interesting materials of the Free Technical Library:

▪ section of the site Spy stuff. Article selection

▪ article by Neil deGrasse Tyson. Famous aphorisms

▪ article How far is the nearest star from us? Detailed answer

▪ article Tsimitsifuga Daurian. Legends, cultivation, methods of application

▪ article UHF Antenna Two spirals. Encyclopedia of radio electronics and electrical engineering

▪ article A glass of milk. Focus Secret


All languages ​​of this page

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua

www.diagram.com.ua
2000-2024