Skin impedance from 1 Hz to 1 MHz
Rosell, J.; Colominas, J.; Riu, P.; Pallas-Areny, R.; Webster, J.G.
Biomedical Engineering, IEEE Transactions on
Volume 35, Issue 8, Aug. 1988 Page(s):649 - 651
Digital Object Identifier 10.1109/10.4599
Summary:The impedance of skin coated with gel but otherwise unprepared was measured from 1 Hz to 1 MHz at ten sites on the thorax, leg, and forehead of ten subjects. For a 1-cm/sup 2/ area, the 1 Hz impedance varied from 10 k Omega to 1 M Omega , which suggests that the bipotential amplifier input impedance should be very high to avoid common-mode-to-differential-mode voltage conversion. The 1-MHz impedance was tightly clustered about 120 Omega . The 100-kHz impedance was about 220 Omega , which suggests that the variation in skin impedance can cause errors in two-electrode electrical impedance tomographs.
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