Low-noise amplification of voltage and current fluctuations arising in epithelia.
Two low-noise differential input amplifiers designed for voltage and current fluctuation measurements in epithelia are described. The first one uses a matched pair of low-noise transistors and is particularly suited for low-frequency current and voltage noise measurements in frog skin and other preparations with impedances below 1 kOmega. The second one is designed around a matched pair of JFETs and can also be used for higher source impedance. Performance is demonstrated with Na(+) current power density spectra obtained from frog skin with the transistor-input stage.
Van Driessche
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Laboratorium voor Fysiologie, Universiteit te Leuven, BelgiumAbteilung fur Membranforschung an Epithelien, Second Department of Physiology, D6650 Homburg, West Germany.
Lindemann
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