Clinical application of an active electrode using an operational amplifier

Abstract

An active electrode (d10 mm, t6 mm) is presented, that functions as an impedance transformer (an input impedance > 10 G omega, an output impedance < 1 omega) by means of which we can derive surface EMG without any skin preparation and paste. This electrode was compared with a conventional one, and it was ascertained that the electrode could be replaced with the conventional one, and, moreover, it was preferable because it required less preparation time, and was less affected by environmental noise.

Towards optimal multi-channel EMG electrode configurations in muscle force estimation: a high density EMG study

“…Previous research has contributed to optimization of the technical aspects, instrumentation [5,8,11,18,29] and appropriate filter techniques [2,19]. A decrease in EMG variability, resulting in an improvement of EMG based force estimation quality, can be obtained when using multiple bipolar electrodes spatially distributed over the muscle belly [4,10].…”

Fabric-Based Active Electrode Design and Fabrication for Health Monitoring Clothing

“…A buffer amplifier is essentially an impedance converter, one that converts high-impedance signals to low-impedance signals [1]. Now, whereas, high-impedance signals are very susceptible to both noise and motion-induced artifacts in signal paths, a lowimpedance signal is virtually unaffected by either of these artifacts [2]. As a result, implementing a simple buffer amplifier at the electrode site reduces the signal impedance and prevents noise generation.…”

Active Wireless Electrodes for Multichannel Surface Electromyography

“…That operates as a differential amplifier and an impedance transformer due to the high input impedance of 10G-W compared with human skin resistance and very low output impedance (3). In the first stage of the instrumentation amplifier, the resistor R and the capacitor C composes a primary high-pass filter to remove contact potentials and its drifts by chemical interaction between human skin and an electrode surface, as depicted in Fig.…”