Electrical impedance

About: Electrical impedance is a research topic. Over the lifetime, 36015 publications have been published within this topic receiving 371891 citations. The topic is also known as: electrical impedance & complex impedance.

System And Method For Measuring Initial Tissue Impedance

Abstract: An electrosurgical system and method are disclosed. The system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue. The generator is further adapted to supply an electrical signal having at least one substantially constant value to tissue to determine initial tissue impedance response. The generator includes sensor circuitry adapted to continuously monitor initial tissue impedance response, wherein the initial tissue impedance response includes one of an initial impedance, an impedance drop, an impedance minimum and a first impedance rise. The generator also includes a microprocessor adapted to generate at least one tissue parameter based as a function of the initial impedance, the impedance drop, the impedance minimum and the first impedance rise. The system also includes an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue for treatment.

Impedance spectroscopy study of polycrystalline Bi6Fe2Ti3O18

Abstract: The electrical properties of polycrystalline Bi6Fe2Ti3O18 are investigated by impedance spectroscopy in the temperature range 30–550°C. The imaginary part of impedance as a function of frequency shows Debye like relaxation. Impedance data are presented in the Nyquist plot which is used to identify an equivalent circuit and the fundamental circuit parameters are determined at different temperatures. The grain and grain-boundary contributions are estimated. The results of bulk a.c. conductivity as a function of temperature and frequency are presented. The activation energies for the a.c. conductivity are calculated. The polaron hopping frequencies are estimated from the a.c. conductivity data.

Quadrature Oscillators with Grounded Capacitors and Resistors Using FDCCIIs

Abstract: Two current-mode and/or voltage-mode quadrature oscillator circuits each using one fully-differential secondgeneration current conveyor (FDCCII), two grounded capacitors, and two (or three) grounded resistors are presented. In the proposed circuits, the current-mode quadrature signals have the advantage of high-output impedance. The oscillation conditions and oscillation frequencies are orthogonally (or independently) controllable. The current-mode and voltage-mode quadrature signals can be simultaneously obtained from the second proposed circuit. The use of only grounded capacitors and resistors makes the proposed circuits ideal for integrated circuit implementation. Simulation results are also included.

Transmission-line missile antennas

Abstract: A class of protruding rocket antennas of low silhouette is analyzed in terms of an approximately equivalent circuit that consists of a shunt-driven transmission line terminated in a reactor at each end. Expressions for the currents in the several parts of the circuit are used to determine the Poynting vector and from this the radiation resistance referred to the current in the generator. The reactance is obtained from transmission-line formulas.

Filter structures for integrated circuit interfaces

Abstract: A method of optimizing the frequency response of an interconnect system of the type which conveys high frequency signals between bond pads of separate integrated circuits (ICs) mounted on a printed circuit board (PCB) through inductive conductors, such as bond wires and package legs, and a trace on the surface of the PCB. To improve the interconnect system, capacitance is added to the trace and inductance is added to the conductors, with the added trace capacitance and conductor inductance being appropriately sized relative to one another and to various other interconnect system impedances to optimize the interconnect system impedance matching frequency response.