Comparative study of ZnCr2O4-K2CrO4 ceramic humidity sensor using computer controlled humidity measurement set-up


Kavasoglu N., Kavasoglu A., Bayhan M.

SENSORS AND ACTUATORS A-PHYSICAL, vol.126, no.2, pp.355-361, 2006 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 126 Issue: 2
  • Publication Date: 2006
  • Doi Number: 10.1016/j.sna.2005.10.049
  • Title of Journal : SENSORS AND ACTUATORS A-PHYSICAL
  • Page Numbers: pp.355-361

Abstract

A home-made ZnCr2O4-KCrO4 ceramic humidity sensor was studied using a commercially available reference humidity sensor, SHT75 from Sensirion. The main advantages of our developed set-up for humidity measurements are low cost and high resolution yielding a full set of information on the variation of humidity. Air moisture sensitive ceramic body prepared using K2CrO4 (20%) in ZnCr2O4 was produced from the solid-state reaction between zinc oxide and chromite oxide at high temperatures. The dc resistance as a function of relative humidity (RH) showed a strong dependence, decreasing over several orders of magnitude with increasing humidity being a smooth exponential. The air moisture dependent resistance of the ceramic sensor is converted into voltage signals using a circuitry. Basically it consists of an operational amplifier and an A/D converter. Long-term stability measurements showed that ZnCr2O4-K2CrO4 ceramic system has potential use as an active material in humidity sensors. (C) 2005 Elsevier B.V. All rights reserved.