Publication: An alternate voltage-controlled current source for electrical impedance tomography applications
Date
2019
Authors
Chitturi V.
Farrukh N.
Journal Title
Journal ISSN
Volume Title
Publisher
Springer
Abstract
The desirable features of any current source in electrical impedance tomography (EIT) are high output impedance and a constant current for varying loads. Howland current sources are the most popular current sources for EIT applications. Alternately, a simple non-inverting amplifier circuit can be used as a voltage-controlled current source using IC LM7171 op-amp. A constant current of 5 mA (PP) is designed and tested over a wide range of frequencies. The frequency response indicates a stable current up to 1 MHz. These results are validated for an impedance of 1 k? which is usually considered for EIT applications. A buffer circuit is added to this current circuit to meet high output impedance matching. A minor discrepancy is visible between the theoretical value and measured value of the output current due to the tolerance band of the resistors used in the non-inverting amplifier circuit. � Springer Nature Singapore Pte Ltd 2019.