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Television antennas. Schemes, articles, descriptions

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Television antennas

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Command device for receiver and transmitter Signal-1



Section Radio control equipment. A clock generator is assembled on the elements DD1.1 and DD1.2, which generates pulses with a repetition rate of approximately 1 Hz (it depends on the capacitance of the capacitor C1 and the resistance of resistors R1 and R2). These pulses are fed to the synchronization input (C) of the DD2.1 trigger, which, together with the DD2.2 trigger, is a two-bit binary counter. Signal LEDs HL3 and HL4 are connected to the inverse outputs of the counter through resistors R1 and R2. They light up when these outputs have a logic level of 0. The direct outputs are connected to the information inputs (D) of the recording device, which is made on triggers DD3.1 and DD3.2. Transistor keys with electromagnetic relays are connected to the outputs of these triggers, as well as the inverter DD1.3, through resistors R7 - R9 - they switch the power circuits of electric motors of models Ml (left) and M2 (right) ... >>

Charger with SHI current regulation



Section Chargers, batteries, galvanic cells. The charger control unit is a pulse generator assembled on the elements DD1.1 and DD1.2 (see the diagram in Fig. 1) and allows you to adjust the duty cycle of the pulses, a buffer amplifier - an inverter on the elements DD1.3 and DD1.4 and a switching regulator element - field effect transistor VT1. With the values ​​\u13b\u1bof the elements indicated on the diagram, the generator frequency is about 0,017 kHz. Since the resistance of the open channel of the transistor VT5 is very small (0,55 Ohm) and it works in switching mode, with a charging current of up to XNUMX A, the transistor practically does not heat up - the dissipated thermal power does not exceed XNUMX W ... >>

UMZCH increased power (for disco) on the STK4231 chip



Section Transistor power amplifiers. UMZCH high power (for disco) is made on a hybrid IC Sanyo STK4231-II. The microcircuit is two-channel, therefore, only one IC package is required to form a bridged load connection BA1. The sound signal to the upper amplifier according to the circuit (pin 3 DA2) comes directly, and to the lower one (pin 20 DA2) - through a single inverter on the op-amp DA1. Output current sensors R18 and R28 in case of overload or short circuit. loads open transistors VT2, VT1, and behind them the analog of the thyristor on VT3, VT4 is latched, closing resistors R25, R31 to ground and turning off the amplifier. L1 and L2 are wound with a millimeter wire in one layer on resistors R17, R29 (C5-16 with a power of 5 W). Due to the high power dissipation, the DA2 IC must be mounted directly on an efficient heat sink (preferably with forced airflow - a fan from the PC processor), preventing it from heating above 70 ° C ... >>

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Articles on television antennas

Articles on television antennas; schemes of television antennas; descriptions of television antennas: 64 articles

 


 

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Latest news of science and technology, new electronics:

Using Apple Vision Pro during surgery 16.03.2024

The medical team at Cromwell Hospital in London used Apple Vision Pro for the first time during two spinal surgeries. This event confirms the headset's potential as a medical tool that will change the way surgical practice is performed. Although the doctors themselves did not use Vision Pro, the operating room nurse worked with virtual reality using glasses while preparing and performing procedures. The headset made it possible to view virtual screens in the operating room, select instruments and monitor the progress of the operation. Software developed by eXeX, a company that specializes in creating artificial intelligence-based applications for surgery, has significantly improved the patient care process. Using Apple Vision Pro opens up new opportunities for developing healthcare applications such as clinical education, surgical planning, training and medical imaging. Implementation of Apple Vision Pro in the medical industry ... >>

Carbon storage in the North Sea 16.03.2024

Norwegian Energy Minister Terje Åsland has announced the launch of the Longship project, which aims to create a central carbon dioxide storage facility in the North Sea. This ambitious project is valued at $2,6 billion and aims to apply CCS (carbon capture and storage) technology to mitigate the impact of climate change. Norway already has experience in CCS, thanks to the successful Sleipner and Snohvit projects, and is now looking to increase the amount of carbon sealed beneath the seabed. Longship's plan calls for capacity to capture and store 1,5 million tons of carbon annually over 25 years. Despite the positive outlook, there are concerns about the long-term consequences of such storage. However, proponents of the project argue that offshore carbon storage has a number of advantages, including minimal environmental impact. The Longship project is carried out with the participation of Equinor, Shell and TotalEnergies through the joint venture Northern Li ... >>

Mini-organs grown from human amniotic fluid 15.03.2024

An international team of scientists led by Professor Fan Xiulin from Zhejiang University has developed a unique method of growing mini-organs from cells found in human amniotic fluid. This significant medical breakthrough could lead to improved diagnosis and treatment of congenital diseases. The organoids, which are three-dimensional cellular structures that mimic organs on a smaller scale, were grown from lung, kidney and small intestine cells found in amniotic fluid. This method opens up new possibilities for studying various fetal conditions and may be the key to early diagnosis and treatment of birth defects. Although no treatment has yet been attempted, the scientists hope their research will help combat the serious congenital diseases that affect millions of newborns each year. This breakthrough could change medical interventions by making it possible to diagnose and treat congenital diseases. ... >>

Random news from the Archive

Laser X-ray machine detects radioactive contraband 04.01.2016

For the first time since 1988, the production of plutonium-238 resumed at the Oak Ridge National Laboratory of the US Department of Energy. This unstable isotope, with a half-life of 87,7 years, is used in spacecraft radioisotope generators, and until recently NASA "ate" the plutonium-238 purchased from Russia in 1993. But given that not all of the remaining plutonium meets the required specifications, the Russian isotope is enough for another 2-3 missions. And the new production line will be able to produce 300-400 g per year with an increase in production up to 1,5 kg per year in the future.

However, the Department of Energy is concerned not only about a possible shortage of radioactive materials, but also about their falling into the wrong hands domestically - for example, through more than 100 million containers arriving annually in the United States. Only a small proportion of them pass through customs, and containers with a high degree of national security risk are checked using X-ray and gamma-ray installations and detectors of radioactive materials. But such installations are huge in size and are not able to detect a small amount of radioactive material hidden inside a shielded container.

The solution to the problem was proposed by researchers from the American University of Nebraska in Lincoln. They figured out how to make a laser X-ray machine that can detect a uranium disk the size of three dime coins hidden between 10 cm thick steel panels. developed by university scientists in 7,5. The machine emits a highly focused X-ray beam, similar to a laser pointer, that can travel a considerable distance and detect radioactive material on ships before they enter port.

According to the researchers, the new facility is about the size of a truck trailer, is much safer than existing devices, and has a detection capability far beyond the 1kg mass of uranium required by the standard. The facility was developed with a grant from the US Department of Homeland Security's Office for Nuclear Discovery.

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