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Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
Except in the case of very short-range, low-power radios, PA components tend to be discrete devices with minimal levels of integration. The unique semiconductor and thermal requirements of power amplifiers dictate the use of unique fabrication and manufacturing techniques in order to obtain required performance. The power and frequency requirements of the application typically dictate what device technology is required for the power amplifier. At frequencies as low as 1GHz and power levels of 1 watt, compound semiconductor devices often compete with silicon and SiGe for power amplifier devices. As power and frequency increase from these levels, compound semiconductor HEMTs dominate in this application. Vacuum tube technology is still required to achieve performance for some extremely highpower or high-frequency applications.
Very-Large-Scale Integration Technology: History and Features
Published in A. Arockia Bazil Raj, FPGA-Based Embedded System Developer's Guide, 2018
Before we learn about field programmable gate arrays (FPGAs) and building the digital systems inside them, let us have a look at what very large scale integration (VLSI) technology is; how it reduces the size of electronic circuits, making their function faster and more reliable; and its uses. The invention of the transistor was the driving factor of growth in VLSI technology. Electronics deals with circuits which involve various active and passive components. These circuits are used in various electronic devices and are called electronic systems. Originally, the components used in electronic systems, like diodes, were made up of vacuum tubes and were called discrete components. Later, when the solid state device (SSD) was invented, the components were made up of semiconductors. Vacuum tubes had the disadvantage of size, power requirements and reliability [1]. An integrated circuit (IC) is the circuit in which all the passive and active components are fabricated onto a single chip. Initially, the integrated chip could accommodate only a few components, but over time, the devices became more complex and required more circuits, which made the devices look bulky. Instead of accommodating more circuits in the system, integration technology was developed to increase the number of components that are to be placed on a single chip.
Power Vacuum Tube Applications
Published in Jerry C. Whitaker, Power Vacuum Tubes, 2017
Although low-power vacuum tubes have been largely replaced by solid-state devices, vacuum tubes continue to perform valuable service at high-power levels and, particularly, at high frequencies. The high-power capability of a vacuum device results from the ability of electron/vacuum systems to support high-power densities. Values run typically at several kilowatts per square centimeter, but may exceed 10 MW/cm2. No known dielectric material can equal these values. For the foreseeable future, if high power is required, electron/vacuum devices will remain the best solution.
Development and thermodynamic analysis of a novel heat pipe vacuum tube solar collector with sensible heat storage
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Anshul Sachdeva, Chandrashekara M., Avadhesh Yadav
The HPVT solar collector facing south is exposed to sunlight. Selective coating on vacuum tube absorbs solar radiations and transfers heat to aluminum fin which is put inside the vacuum tube. Aluminum fin then transfers heat to the copper heat pipe which is in direct contact with the aluminum fin. Heating of copper heat pipe then promotes evaporation of fluid inside it thus causing accumulation of heat in the condenser of copper heat pipe. HTF is filled in to the collector through sump. It is forced to flow in to header through connecting pipes by using the rotary gear pump. HTF gains heat by coming in direct contact with the outer wall of condenser resulting in condensation of fluid inside the copper heat pipe. HTF is then routed to the sump and cycle of heating is repeated providing a consistent operation. This hot HTF can be used for various medium temperature domestic as well as industrial applications such as solar air heating, solar drying, solar water heating, and solar indirect cooking.
Historical Developments and Recent Advances in High-power Magnetron: A Review
Published in IETE Technical Review, 2022
Patibandla Anilkumar, Dobbidi Pamu, Tapeshwar Tiwari
In 1910, Hans Gerdien [3] of Seimens Corporation invented a cylindrical-shaped first tube with a coaxial magnetic field, an electromagnetic field source. In 1912, Heinrich Greinacher, a physicist, developed new ways of calculating electron mass and settled on a diode system consisting of a rod-shaped cathode surrounded by a cylindrical anode in the middle of the magnets. This development was unsuccessful due to improper maintenance of the vacuum system. Thereby, he solved the mathematical models of the motion of the electrons in the crossed electric and magnetic fields. In 1921, Albert W. Hull (New York) [5] coined the name of the magnetron. The Hull’s magnetron circuit is shown in Figure 2, a coaxial diode in a glass vacuum tube with an axial magnetic field. In 1924-30, Erich Habann described the first real magnetron oscillator using a split-anode to generate higher frequency oscillations but has lower efficiency. He discovered that the magnetron could create waves of 100 MHz to 1 GHz. In 1925, it was observed that the Hull magnetron was able to generate relatively high output power at an operating frequency of 20 kHz in the dynatron mode.
Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation
Published in Journal of Nuclear Science and Technology, 2022
Kazami Yamamoto, Michikazu Kinsho, Naoki Hayashi, Pranab Kumar Saha, Fumihiko Tamura, Masanobu Yamamoto, Norio Tani, Tomohiro Takayanagi, Junichiro Kamiya, Yoshihiro Shobuda, Masahiro Yoshimoto, Hiroyuki Harada, Hiroki Takahashi, Yasuhiro Watanabe, Kota Okabe, Masahiro Nomura, Taihei Shimada, Takamitsu Nakanoya, Ayato Ono, Katsuhiro Moriya, Yoshio Yamazaki, Kazuaki Suganuma, Kosuke Fujirai, Nobuhiro Kikuzawa, Shin-Ichiro Meigo, Motoki Ooi, Shuichiro Hatakeyama, Tomohito Togashi, Kaoru Wada, Hideaki Hotchi, Masahito Yoshii, Chihiro Ohmori, Takeshi Toyama, Kenichirou Satou, Yoshiro Irie, Tomoaki Ueno, Koki Horino, Toru Yanagibashi, Riuji Saeki, Atsushi Sato, Osamu Takeda, Masato Kawase, Takahiro Suzuki, Kazuhiko Watanabe, Tatsuya Ishiyama, Shinpei Fukuta, Yuki Sawabe, Yuichi Ito, Yuko Kato, Kazuo Hasegawa, Hiromitsu Suzuki, Fumiaki Noda
At the end of June 2020, we attempted to operate the 1 MW beam continuously for 43 h. On this occasion, immediately after the trial start, two failures occurred in the capacitor and the vacuum tube in the final-stage amplifier of the RF cavity. The beam operation stopped for ~12 h. Therefore, although the duration of the 1 MW trial became shorter than originally planned, we still performed continuous operation for 36 h by increasing the operation period. In this continuous operation, we again confirmed that there were no problems with foil durability, vacuum pressure increases, and beam losses. Whereas it was found that when the outside temperature increased, the supply temperature of cooling water became uncontrollable and increased. This led to the temperature interlock of the vacuum tube in the RF final stage amplifier. Details regarding this issue are discussed in Section 4.2.4. In terms of the failure of the capacitor and the vacuum tube, we believe the primary cause was attributed to age-related deterioration, and the operation condition of 1 MW beam did not directly cause any significant deterioration.