Calibration-less direct capacitor-to-microcontroller interface
A new technique to measure a capacitor or a capacitive sensor by means of a direct sensor-to-microcontroller interface circuit that does not need a calibration capacitor is proposed. Basically, the measurement process consists of three consecutive steps of charge, discharge and charge of the capacit...
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Published in | Electronics letters Vol. 52; no. 4; pp. 289 - 291 |
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Main Authors | , , |
Format | Journal Article Publication |
Language | English |
Published |
The Institution of Engineering and Technology
18.02.2016
Institution of Electrical Engineers |
Subjects | |
Online Access | Get full text |
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Summary: | A new technique to measure a capacitor or a capacitive sensor by means of a direct sensor-to-microcontroller interface circuit that does not need a calibration capacitor is proposed. Basically, the measurement process consists of three consecutive steps of charge, discharge and charge of the capacitor under test. A non-linear equation is obtained and solved that is dependent only on known circuit parameters. Experimental results show that it is possible to measure a wide range of capacitor values with a maximum deviation of 2% from the reference value, and that temperature changes from 18 to 70°C yield relative errors below 0.1%. For the lowest measured capacitor range (33 pF–4.7 nF) the uncertainty holds below 1 pF which enables measurement of commercially available capacitive sensors. The main advantage of the proposed technique is cost and space reduction of the final design. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0013-5194 1350-911X 1350-911X |
DOI: | 10.1049/el.2015.3706 |