Non-invasive Human Body Electrophysiological Measurements using Displacement Current Sensors

Harland, C J, Clark, T D and Prance, R J (2004) Non-invasive Human Body Electrophysiological Measurements using Displacement Current Sensors. In: 1st International Workshop on Wearable and Implantable Body Sensor Networks, London.

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We describe the displacement current (electric potential) sensor for use in the non-invasive detection of human body electrical signals. The sensor, based on commercially available electrometer amplifiers, operates by monitoring the displacement current (effectively an electric field changing with time) between the body and the sensor input electrode. By adopting various electronic feedback techniques, combined with bias and stabilization circuits, we have been able to greatly enhance the input impedance and sensitivity of these amplifiers compared with the standard electrode systems in use today. In our current systems input impedances are typically 10-15¿, with a minimum noise floor of 30nV/vHz at 1Hz. With this capability these sensors can be used to record body electrical signals remarkably well. Furthermore, since no real charge current is required for these sensors to function, we are able to dispense with the usual electrolytic paste contact to the surface of the body. As a consequence displacement current sensors are perfectly bio-compatible. In this paper we provide several applications of these sensors, in particular to the ECG and EO.

Item Type: Conference or Workshop Item (Paper)
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Depositing User: Christopher Harland
Date Deposited: 06 Feb 2012 20:15
Last Modified: 24 Jun 2015 12:37
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