Comparison of IR LED gas sensors with thermal source products

Author

Smith, S.D. ; Vass, A. ; Bramley, P. ; Crowder, J.G. ; Wang, C.H.

Author_Institution

Edinburgh Sensor Ltd., Livingston, UK

Volume

144

Issue

5

fYear

1997

fDate

10/1/1997 12:00:00 AM

Firstpage

266

Lastpage

270

Abstract

Physical principles for infrared gas sensing using LEDs as sources are examined. A number of LEDs from different sources are compared for power output, polar diagram and temperature dependence of output. Some of these have been incorporated in a practical gas sensor based on the Edinburgh Sensors´ Gascard. Thus a direct comparison of signal levels between thermal sources and LEDs has been made using thermal detectors. Gas sensing is demonstrated for CO₂. The paper describes the ranges, accuracies and stability with time and temperature presently exhibited by thermal source sensors and suggests criteria for the widespread use of LED sensors. Some advanced concepts are mentioned with respect to future sensing requirements

Keywords

gas sensors; infrared sources; light emitting diodes; measurement errors; numerical stability; CO₂; Edinburgh Sensors´ Gascard; IR LED gas sensors; infrared gas sensing; measurement accuracy; measurement range; physical principles; polar diagram; power output; practical gas sensor; signal levels; temperature dependence; thermal detectors; thermal source products; thermal sources;

fLanguage

English

Journal_Title

Optoelectronics, IEE Proceedings -

Publisher

iet

ISSN

1350-2433

Type

jour

DOI

10.1049/ip-opt:19971510

Filename

674326