Portable radio stations. Schemes, articles of the Free Technical Library

FREE TECH LIBRARY
Free library / Schemes of radio-electronic and electrical devices

Portable radios. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

Portable radio stations

We recommend reading in our Free Technical Library:

Radio station Astra-1-FM-CB

Section Civil radio communications. The radio station operates on one fixed frequency in the 27 MHz band (in this case 27,12 MHz), with frequency modulation. It has quartz frequency stabilization of both the receiver and the transmitter. With the same type of radio station provides communication in open areas within a radius of up to 3 KM, in urban areas up to 1 KM, depending on specific circumstances ... >>

Structural diagram of electronic ballast

Section Ballasts for fluorescent lamps. Consider the principle of operation of a simple electronic ballast using the IR2153 microcircuit as an example. On the structural diagram of the electronic ballast (Fig. 3.13), point A is connected using the keys Kl1 and Kl2 either to the supply voltage (Up = +310 V), or to the common wire. The keys, recharging the capacitor, form a portable voltage. As a result, unipolar high-frequency voltage pulses occur at point A (the switching frequency is usually in the range of 30-100 kHz), which, firstly, ignite the lamp, and, secondly, prevent the gas from deionizing (no flicker). With this method of starting and controlling, a false start is completely excluded, since the lamp is guaranteed to be switched to a constant voltage, the dips of which are fundamentally absent. The dimensions of the inductive element are reduced. By adjusting the duty cycle (or phase) of the switching pulses, you can achieve a change in the brightness of the glow ... >>

Switching voltage regulator, 20-35/15 volts 1 amp

Section Voltage stabilizers. Due to their high efficiency, switching voltage stabilizers have recently become more widespread, although they are usually more complicated than traditional ones and contain a larger number of elements. However, if you do not impose excessive requirements on the stability and ripple of the output voltage, then their circuit can be greatly simplified. So, for example, a stabilizer with an output voltage lower than the input voltage can be assembled on only three transistors (see figure), two of which (VT1, VT2) form a key regulatory element, and the third (VT3) is an error signal amplifier ... >>

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

Articles on portable radios

Articles on portable radio stations; schemes of portable radio stations; descriptions of portable radios: 37 articles

All articles on civil radio communication

Latest news of science and technology, new electronics:

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

The threat of space debris to the Earth's magnetic field 01.05.2024

More and more often we hear about an increase in the amount of space debris surrounding our planet. However, it is not only active satellites and spacecraft that contribute to this problem, but also debris from old missions. The growing number of satellites launched by companies like SpaceX creates not only opportunities for the development of the Internet, but also serious threats to space security. Experts are now turning their attention to the potential implications for the Earth's magnetic field. Dr. Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics emphasizes that companies are rapidly deploying satellite constellations, and the number of satellites could grow to 100 in the next decade. The rapid development of these cosmic armadas of satellites can lead to contamination of the Earth's plasma environment with dangerous debris and a threat to the stability of the magnetosphere. Metal debris from used rockets can disrupt the ionosphere and magnetosphere. Both of these systems play a key role in protecting the atmosphere and maintaining ... >>

Solidification of bulk substances 30.04.2024

There are quite a few mysteries in the world of science, and one of them is the strange behavior of bulk materials. They may behave like a solid but suddenly turn into a flowing liquid. This phenomenon has attracted the attention of many researchers, and we may finally be getting closer to solving this mystery. Imagine sand in an hourglass. It usually flows freely, but in some cases its particles begin to get stuck, turning from a liquid to a solid. This transition has important implications for many areas, from drug production to construction. Researchers from the USA have attempted to describe this phenomenon and come closer to understanding it. In the study, the scientists conducted simulations in the laboratory using data from bags of polystyrene beads. They found that the vibrations within these sets had specific frequencies, meaning that only certain types of vibrations could travel through the material. Received ... >>

Random news from the Archive

The risk of the American diet 24.07.2015

It is well known that many Americans do not consume the healthiest foods. For example, it has few plant fibers, but a lot of animal fats and proteins. One of the consequences is a high level of bowel cancer, 65 cases per 100 inhabitants. But where they eat rough, low-fat foods with a lot of fiber, for example, in rural areas of South Africa, the incidence rate is only 5 people per hundred (100) thousand.

Researchers from the University of Pittsburgh, led by Professor Stephen O'Keefe, together with colleagues from King's College London, conducted an experiment involving twenty black volunteers from the United States and South Africa. During the examination, every second American found polyps in the intestines, which may well develop into malignant tumors. Africans didn't have that. Then the participants in both groups changed their diet.

The result amazed the researchers: in the first, inflammatory processes began to decline, and biomarkers of the risk of developing cancer, which is determined by the composition of intestinal mucus, decreased sharply. The latter, on the contrary, grew sharply. And all this in just two weeks! By itself, the effect of changing the diet has long been known - for example, in Japanese who moved to live in Hawaii and became addicted to American food, in just one generation, a low incidence of bowel cancer changes to a high one.

"The rapid westernization of African lifestyles in response to these data is alarming," says Prof O'Keeffe. "On the other hand, the fact that a traditional African diet high in fiber reduces risk in just two weeks may be a good sign that never will." It's not too late to reverse the process."

The reason is considered to be a significant increase in the production of butyric acid and its derivatives by intestinal microbes during the assimilation of dietary fiber: these substances inhibit tumor cells and promote the development of normal epithelial cells.

Dietary fiber - cellulose, lignin, pectin and other polysaccharides that are not digestible, but good for health - this is what bran, dried apples, apricots and raisins, black bread, fried mushrooms and other plant products are rich in primarily.

Other interesting news:

▪ i-Disk BulletProof

▪ Sabrent Rocket NVMe 4.0 High Speed 1TB SSD

▪ Underground passages of old Europe

▪ Languages of the future

▪ Metals in champagne

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Electrician's tool. Article selection

▪ Article Regulation obliges. Popular expression

▪ article Why can't we see colors in the dark? Detailed answer

▪ article Meadowsweet meadowsweet. Legends, cultivation, methods of application

▪ article Antenna amplifier for a radio transmitter. Encyclopedia of radio electronics and electrical engineering

▪ article Finely compensated volume control on a resistor without taps. Encyclopedia of radio electronics and electrical engineering

All languages of this page

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