Auto-balancing method development for the Wheatstone bridge to detect harmonics: implementation on 3omega hot wire method

Ateş İ., Doğanay S., Çetin L., TURGUT A., Chirtoc M.

Measurement Science and Technology, vol.36, no.6, 2025 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 36 Issue: 6
  • Publication Date: 2025
  • Doi Number: 10.1088/1361-6501/add6bf
  • Journal Name: Measurement Science and Technology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Analytical Abstracts, Applied Science & Technology Source, Chemical Abstracts Core, Communication Abstracts, Compendex, Computer & Applied Sciences, INSPEC, Metadex, Civil Engineering Abstracts
  • Keywords: Wheatstone bridge, automatic bridge balancing, high sensitivity harmonic detection, 3omega hot wire method, thermophysical characterization
  • Dokuz Eylül University Affiliated: Yes

Abstract

The goal of this study is to develop an automatic balancing method for the accurate detection of harmonics in the 3omega hot wire (3ωHW) method for the thermal conductivity measurement of liquids. To detect harmonics, an essential requirement is the elimination of the fundamental voltage on bridge output caused by the excitation. For this purpose, a closed-loop control circuit exploiting a digitally controlled potentiometer was designed and an application-specific algorithm was developed to manage the bridge balancing automatically. The developed method was then integrated into the conventional 3ωHW method to eliminate uncertainties in the manual balancing process. Following, the performance tests were carried out with the auto-balanced 3ωHW setup in the dynamic range of thermal conductivity 0.127-0.710 W m−1 K−1, including both base fluids and nanofluids. The ratio between the 3ω voltage and the fundamental one is enhanced from 10−4 to approximately 100 in 3.7 s without any manual adjustment.