KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Sriratana, WitsarutSubject: search.filters.subject.Capacitance

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Development of a Capacitive Sensing Module to Detect the Concentration of Isopropyl Alcohol for Covid-19 Disinfection Using Small Capacitance to DC Converter
    (2024-01-01)
    Sriratana, Witsarut
    ;
    Faijaree, Manasnit
    ;
    Sriratana, Lerdlekha
    ;
    Satthamsakul, Sutham
    This paper presents the development of a sensing module for analyzing the concentration of disinfectant alcohol commercially available in Thailand during the Covid-19 epidemic situation to ensure the ingredients and percentage concentration by focusing on simplicity, low cost with reliable performance. Under the basic physical structure of the capacitance change [1]-[5], it consists of a New Sensor Module developed to fully interface with the small capacitance to DC converter for capacitive sensor [2] model. Inside the sensing structure, there were 2 modules of metal conductors. Each conductor was 3 mm. thick, placed in parallel with a fixed distance between the module of 1 mm. The cross-sectional areas of the plates of those two modules were different in order to compare the efficiency of the detector developed. The cross-sectional areas of the plates of Module A and B were 4 cm<sup>2</sup> and 1 cm<sup>2</sup>, respectively. Experiments were performed with 3 concentrations of alcohol, 65%, 70% and 75%, to enhance the concentration detecting performance of the sensing module developed. The signal conditioning was generated from a small capacitance to DC converter for capacitive detection with a frequency of 100 kHz, which was the most suitable frequency for exciting the capacitance change which was the capacitive reactance of the alcohol used in this study. From experiments, it was found that the sensing module with a small cross-sectional conductive material would provide more accurate results in terms of linearity and repeatability. The errors were less than 2.72% compared to the module with a large cross-sectional conductor material which would have an error up to 4.73%.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Design of capacitive sensor for concentration measurement
    (2006-12-01)
    Thong-un, Natee
    ;
    Sriratana, Witsarut
    ;
    Tanachaikhan, Lerdlekha
    This paper presents the analysis of ideal equivalent circuit of the developed concentration sensor probe for chemical solutions by regarding to reasonable costs and reliability of device. The designed sensor probe consists of 2 parallel electrode plates that are coated by Nylon with 0.4 mm thick and mounted together by Resin with 2.5 mm of gap (0.09 times greater than electrode width). Any capacity changes will be compared with the electric circuit that is obtained from the Good Will R-L-C standard instrument, model CTR, at the frequency extending from 100Hz to 2 kHz. From the experiments, it was found that the sensor designed for Ethyl Alcohol solution within concentration of 5% to 95% and 10% concentration interval, at room temperature of 23°C and frequency of 100 Hz, can provide the results with high linearity as well as high resolution of capacity change which is 2 pF per 1% of concentration. © 2006 ICASE.