Miscellaneous civil radio communication devices. Schemes, articles of the Free Technical Library

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Miscellaneous civil radio communication devices. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

Miscellaneous civil radio communication devices

We recommend reading in our Free Technical Library:

Portable transistor radio station for 144-146 MHz (retro)

Section Civil radio communications. Schematic diagram of the radio station is shown in fig. 1. It is made on four transistors. The transmitter is assembled according to the scheme with extraneous excitation. Oscillations at fixed frequencies in the range of 72-73 MHz, generated by the exciter assembled on the transistor T3 (OS 614), are modulated in frequency by applying an alternating voltage from the carbon microphone capsule of the Central Bank to the base circuit of the transistor T3. This voltage changes the dynamic capacitances of the transistor, which ultimately makes it possible to obtain very good frequency modulation with a frequency deviation of up to 0,5 MHz at a low supply voltage. ... >>

Pyroelectric signaling device in the security system

Section Security devices and signaling of objects. Pyroelectric infrared radiation sensors have a fairly high sensitivity, are easy to connect and relatively inexpensive. However, as practice shows, often cheap sensors are prone to spontaneous (false) alarms. So, the most affordable and widely used SRP PLUS sensors gave an average of one or two false positives in about eight hours. For this reason, the use of pyroelectric sensors in security systems requires the adoption of measures to combat false positives. The device described below allows you to successfully use almost any pyroelectric sensor for reliable protection of the premises. The sensor is an independent electronic unit, to which a supply voltage of 12 V is connected. In the absence of movement in the sensor's field of view, the resistance between the Relay pins is minimal (several tens of ohms - contacts are closed), when triggered, it increases to tens of mOhms (contacts are open). The minimum response time of the sensor is 2...3 s, even if the object moves quickly in the sensitivity zone. For occasional false alarms, this time is usually not exceeded. ... >>

GAINCLONE-2007. ULF on the LME49810 chip

Section Transistor power amplifiers. Having received a press release and samples of new microcircuits from National Semiconductor Co (NSC) in the spring, I could not help but pay attention to the LME49810, and immediately began the project, which I dubbed the GainClone-2007 working title. This name came to my mind immediately, because it was simply impossible not to notice the attractiveness of this microcircuit. One study of the press release was enough to see that the LME49810 is not just a microcircuit, the LME49810 is a fighter for Levinsons, Brystones, Krells, Akuphases, Links, and everything on a discrete. I foresee the brightest future for her and no less popularity than the LM3886, which became the basis of the first Gainclone, the most popular repeating amplifier in the world, received in its time. ... >>

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Articles on various civil radio communication devices

Articles on various civil radio communication devices; diagrams of various civil radio communication devices; descriptions of various civil radio communication devices: 12 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 ... >>

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Boost Voltage Converter NCP5007 21.02.2005

ON SEMICONDUCTOR NCP5007 step-up voltage converter is designed to power a set of 5 white LEDs, for which it provides an output voltage of up to 22

V at a supply voltage of 2,7 to 5,5 V. The microcircuit has built-in overload protection, a standby mode in which it consumes only 0,3 μA, thermal protection and a low level of external radiation. Available in a compact TSOP-5 package.

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