Sensitivity enhancement for gas sensing and electronic nose applications

✍ Scribed by H.V. Shurmer; P. Corcoran; M.K. James

• Book ID: 103960733
• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 394 KB
• Volume: 16
• Category: Article
• ISSN: 0925-4005
• DOI: 10.1016/0925-4005(93)85191-c

✦ Synopsis

The sensitivity of varistor types of gas detector may be severely restricted by conventional techniques of deriving the system input signal from a voltage change arising from a dual-arm potential divider. A much more effective means of analogue signal processing for high sensitivity can be achieved through the use of a.c. bridge methods, together with narrow-band filtering to enhance the signal-to-noise ratio. Such methods have been applied to commercial tin dioxide sensing devices intended for use in an electronic nose and we present results showing them to give sensitivity improvements of about two orders of magnitude, with an expectancy of further improvement following circuit refinement. The techniques are equally applicable to the sensing of individual gases, gas mixtures or complex odours.