A Low-Cost Precision Electrode Impedance Meter

Authors

  • W. J. Ross Dunseath

    Corresponding author
    1. Department of Electrical Engineering, Duke University
      Address requests for reprints to: Ross Dunseath. Department of Electrical Engineering. Duke University. Durham, North Carolina 27706.
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  • Thanks to Dr. Alan J. Fridlund for suggesting this calibration configuration.

  • The author expresses his appreciation lo Edward Kelly. Ph.D. and Fritz Klein, Ph.D. for their assistance.

  • This work was supported by the McDonnell Foundation.

Address requests for reprints to: Ross Dunseath. Department of Electrical Engineering. Duke University. Durham, North Carolina 27706.

ABSTRACT

A circuit is described which measures applied electrode impedances using a 7 P.A RMS, 10 Hz sine wave current, and displays the reading in ohms on a small analog meter. The design uses a minimum of parts and power, drawing only 2mA from a 9 volt battery, yet is accurate lo within 2% and can easily be modified to fit a wide range of frequencies.

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