How are ECG signals acquired by sensing electrodes?
The ECG signals are acquired by the two sensing electrodes attached on the human body, then forwarded into the ECG detector. In the ECG detection unit, as can be seen in Fig. 11.3, the ECG detector comprises low pass filter (LPF), band elimination filter (BEF), and differential amplifiers.
What are the requirements for a sensing electrode?
The major design requirement for the sensing electrodes is that they have a minimum scattering effect on the current distribution. They should therefore be high-impedance elements. The ECG signals are acquired by the two sensing electrodes attached on the human body, then forwarded into the ECG detector.
How does gas react at the sensing electrode?
The gas that diffuses through the barrier reacts at the surface of the sensing electrode involving either an oxidation (CO, H2 S, NO, SO 2, etc.) or reduction (NO 2 and Cl 2) mechanism. These reactions are catalyzed by electrode materials specifically developed for the gas of interest ( Davis et al., 2011 ).
How are needle electrodes different from fine wire electrodes?
Needle electrodes are metal electrodes similar to fine wire electrodes. However, needle electrodes are usually much bigger and more robust than fine wire wires. Needle electrodes are usually made out of stainless steel, however a variety of metal alloys can be employed.
The ECG signals are acquired by the two sensing electrodes attached on the human body, then forwarded into the ECG detector. In the ECG detection unit, as can be seen in Fig. 11.3, the ECG detector comprises low pass filter (LPF), band elimination filter (BEF), and differential amplifiers.
Is there a foreign body response to electrodes?
The brain tissue response of chronically implanted electrodes would be less of an issue if the foreign body response disappeared a few weeks after implantation as observed with stab wounds. However, once the acute inflammatory response declines, a chronic foreign body reaction is observed.
The gas that diffuses through the barrier reacts at the surface of the sensing electrode involving either an oxidation (CO, H2 S, NO, SO 2, etc.) or reduction (NO 2 and Cl 2) mechanism. These reactions are catalyzed by electrode materials specifically developed for the gas of interest ( Davis et al., 2011 ).
How are sensing electrodes different from point electrodes?
A low impedance electrode of large area serves to rapidly distribute the current more uniformly than does a point electrode. The sensing electrodes, on the other hand, serve only as detecting elements and they should be made as small as possible.
