Bio Potential Electrodes
The human body generates electrical signals on the body surface.
Recording electrodes picks the bioelectric events produced in the body.
The picked up signals are given to the amplifier and then to display.
Electrodes transfer ionic conduction in the tissue to electronic conduction to measure the values.
Generally, there are two types of electrodes namely surface electrodes and needle electrodes.
A surface electrode picks the potential difference from the tissue surface without damaging the live tissue.
Deep electrode indicates the electric potential value from inside the cell.
The difference between the potential at zero current and the measured potential while current is passing is known as over voltage
and is the result of an alteration in the charge distribution in the solution in contact with the electrodes or the ion selective membrane.
This effect is known as polarization
and can result in diminished electrode performance, especially under conditions of motion.
There are three basic components to the polarization over potential: The ohmic, the concentration, and the activation over potentials.
They pass a current between the electrode and the electrolytic solution by changing the charge distribution within the solution near the electrode.
Thus no actual current crosses the electrode-electrolyte interface.