[show abstract][hide abstract] ABSTRACT: A novel drive circuit, useful for medical electronics, is capable of supplying a sample of human tissue, across which there should be zero direct voltage (dc), with a well-defined test current from a source having an output impedance exceeding 16 MOmega at 100 kHz.
[show abstract][hide abstract] ABSTRACT: Two simple but effective methods are proposed for determining from simulation tests using SPICE parameter data, the incremental collector-base resistance, r<sub>μ</sub>, of the hybrid-π model of bipolar junction transistor (B.J.T.), operating under specified d.c. conditions, from its SPICE parameter set.
Circuit Theory and Design, 2005. Proceedings of the 2005 European Conference on;
[show abstract][hide abstract] ABSTRACT: A new technique is proposed in this paper in order to design a current source in bipolar technology with very high output resistance while minimising output capacitance. Such techniques are useful in Electrical Impedance Tomography applications. First of all, D.C. relationships are established. Then, an expression based on the analysis of a simplified equivalent circuit, is formulated for the output resistance and tested against simulation results for both ideal and practical biasing circuits. The effect of circuit capacitances, and in particular the role of the collector-base capacitance of the output transistor, in determining the output impedance as a function of frequency is considered. Finally, some new circuits with output impedances much greater than that of the basic Baxandall & Swallow (B&S) configuration are proposed and simulated results presented.