title: The performance of integrated transconductance amplifiers as variable current sources for bio-electric impedance measurements.
abstract: Multiple applied current impedance measurement systems require numbers of current sources which operate simultaneously at the same frequency and within the same phase but at variable amplitudes. Investigations into the performance of some integrated operational transconductance amplifiers as variable current sources are described. Measurements of breakthrough, non-linearity and common-mode output levels for LM13600, NE5517 and CA3280 were carried out. The effects of such errors on the overall performance and stability of multiple current systems when driving floating loads are considered.
authors.affiliation: Department of Medical Physics and Medical Engineering, Western General Hospital, Edinburgh, UK.
authors.forename: D N
authors.initials: DN
authors.lastname: Smith
mesh_terms: D000669:Amplifiers, Electronic; D004553:Electric Conductivity; D006801:Humans; D014054:Tomography / Q000295:instrumentation / Q000379:methods*