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Titolo:
A comparison of modified Howland circuits as current generators with current mirror type circuits
Autore:
Bertemes, P; Brown, BH; Wilson, AJ;
Indirizzi:
Univ Sheffield, Royal Hallamshire Hosp, Dept Med Phys & Clin Engn, Sheffield S10 2JF, S Yorkshire, England Univ Sheffield Sheffield S Yorkshire England S10 2JF S Yorkshire, England
Titolo Testata:
PHYSIOLOGICAL MEASUREMENT
fascicolo: 1, volume: 21, anno: 2000,
pagine: 1 - 6
SICI:
0967-3334(200002)21:1<1:ACOMHC>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELECTRICAL-IMPEDANCE TOMOGRAPHY;
Keywords:
current sources; impedance imaging; evaluation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
17
Recensione:
Indirizzi per estratti:
Indirizzo: Bertemes, P Univ Sheffield, Royal Hallamshire Hosp, Dept Med Phys & Clin Engn, Sheffield S10 2JF, S Yorkshire, England Univ Sheffield Sheffield S Yorkshire England S10 2JF England
Citazione:
P. Bertemes et al., "A comparison of modified Howland circuits as current generators with current mirror type circuits", PHYSL MEAS, 21(1), 2000, pp. 1-6

Abstract

Multi-frequency electrical impedance tomography (EIT)) systems require stable voltage controlled current generators that will work over a wide frequency range and with a large variation in load impedance. In this paper we compare the performance of two commonly used designs: the first is a modifiedHowland circuit whilst the second is based on a current mirror. The outputcurrent and the output impedance of both circuits were determined through PSPICE simulation and through measurement. Both circuits were stable over the frequency ranges 1 kHz to 1 MHz. The maximum variation of output currentwith frequency for the modified Howland circuit was 2.0% and for the circuit based on a current mirror 1.6%. The output impedance for both circuits was greater than 100 k Omega for frequencies up to 100 kHz. However, neithercircuit achieved this output impedance at 1 MHz. Comparing the results from the two circuits suggests that there is little to choose between them in terms of a practical implementation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 08/07/20 alle ore 07:52:10