This work describes the design and implementation of the CO2 meter, operated with the PIC18F45K50 microcontroller; which detects the concentration of the gas in parts per thousand (ppm); also, this instrument has an-App downloaded on a mobile device with Android operating system, communicating with the microcontroller via Bluetooth. This to measure the concentration of CO2 which is a colorless gas compound of carbon and oxygen. The measurement of CO2 concentration is a strategy that can warn of the risk of COVID-19 contagion in an enclosed place where a group of people are gathered. In the return to classroom, because the risk of contagion by COVID-19, which is spread through CO2, persists. Also, there are very crowded places due to the daily activities developed by the human being, so now it is not a luxury to take care of the air we breathe to have a healthy life.
This article presents the design and hardware implementation of an IGBT-based half-bridge voltage source inverter (VSI) to be used as a basic cell to assemble VSIs of different topologies in modular ways. Herein, we have presented the design methodology and utilized techniques for reducing stray inductances and EMI radiation on the printed circuit board, as well as the way to calculate and select the main electronic components. For the design of the circuit board, local regulations for grid interconnection and international standards were considered in order to obtain a safe and reliable electronic power cell. The developed hardware was subjected to different tests using AC electric motors as loads to validate its design. Two VSIs topologies were evaluated: a single-phase two-level full-bridge inverter and a three-phase two-level inverter. The experimental results validated the theory and demonstrated the excellent performance, reliability, and high efficiency of the developed half-bridge power cell for modular VSIs.
A comparative analysis was performed of fluorine-doped tin oxide (FTO) thin films deposited through two different systems: pneumatic spray pyrolysis and ultrasonic spray pyrolysis. The films were deposited on glass substrates at 460 °C, with varying weight ratios of fluorine to tin (F/Sn = 0.35, F/Sn = 0.50, and F/Sn = 0.65). The investigation focuses on the evolution of the film’s crystallinity, structural, morphological, transmittance, optical, and electrical properties. Resonant nuclear reaction (RNR) and energy dispersive spectroscopy (EDS) techniques were used to confirm the presence of fluorine in the FTO samples. The results show that the sample with F/Sn = 0.50 deposited through pneumatic spray pyrolysis, with a figure of merit of 34.5 × 10−3 Ω−1, exhibits the best characteristics for use as electrodes in optoelectronic devices, particularly in the fabrication of solar cells.
This work presents the manufacturing and characterization process of two types of transparent conductive oxide (TCO) films, as contacts. Aluminum doped zinc oxide (AZO) deposited with the Sputtering technique and tin doped indium oxide (ITO) using the pyrolysis spray technique, these transparent and conductive films were deposited as contacts on a film of siliconrich oxide (SRO) which was deposited by two systems of chemical vapor deposition by low-pressure (LPCVD) and by hotfilament (HFCVD) on quartz substrates with polysilicon film as metal contact, with the object of building two Metal-InsulatingMetal (MIM) structures, one with SRO-LPCVD film and another SRO-HFCVD thus highlighting the electrical characteristics of these structures. The precursors used for the LPCVD system are silane (SiH4) and nitrous oxide (N2O) and for the HFCVD system the gaseous precursors are obtained from a solid quartz source stripped with atomic hydrogen. First, we present results of the optical characterizations of the TCO´s and SRO films, the band gap obtained by Tauc to calculate the size of the nanocrystal in SRO-films, causing light spots. And I-V curves of MIM structures with interesting results.
This paper presents the results obtained by the electrooptical characterization of a MIS structure built by depositing a film of an Indium Tin Oxide (ITO) on a Silicon Rich Oxide (SRO) film using the Chemical Vapor Deposition Hot Filament (HFCVD) system. The SROHFCVD films were deposited considering two hydrogen fluxes levels at 25 and 100 sccm, under these conditions we grow single and double films, both being heat treated at 1100 ° C to improve their optical and structural characteristics. Through of the techniques of Null Spectroscopy, XPS and Photoluminescence, it was possible to determine the thickness of the SRO films, quantify the silicon excess present in them and analyze their spectra. These films are used as the active layer in Metal-Insulating-Semiconductor (MIS) structures, such structures were electrically characterized through the I-V curves. From the result of these characterizations a comparison is made between the MIS structures with films virgin (V) and with ones heat-treated (T-T). Characterizations indicate that SRO-HFCVD films with T-T significantly modify the optical and electrical properties of MIS structures, which is promising for the design of integrated optical sensors.
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