Journal of Solution Chemistry

, Volume 1, Issue 5, pp 455–463 | Cite as

A radio-frequency moving-boundary detector

  • Krishnahadi S. Pribadi


A new type of moving-boundary detector is described in which boundaries are detected at platinum ring electrodes situated on the outside of a moving-boundary tube. These rings are part of a bridge circuit operating at radio frequencies. Impedance changes in the region of the rings are converted by a phase-sensitive detector to a voltage output which, when operating in the differential mode, takes the form of a sharp peak as a boundary passes through the rings. Boundary displacements of less then 20 μm can be detected, and a precision of better than 0.02% is obtained in the measurement of boundary velocities in typical transference measurements. The fact that only three electrical leads are required in the detecting circuit gives this detector a decided advantage for high-pressure work. Equally important is the elimination of electrode polarization problems associated with other types of electrical detectors.

Key words

Transference numbers high pressure determination of RF detector 


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Copyright information

© Plenum Publishing Corporation 1972

Authors and Affiliations

  • Krishnahadi S. Pribadi
    • 1
  1. 1.Department of ChemistryCarnegie-Mellon UniversityPittsburgh

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