Electrode Whewell at Faraday's request). The anode is now defined as the electrode at which electrons leave the cell and oxidation occurs (indicated by a minus symbol, "−"), and the cathode as the electrode at which electrons enter the cell and reduction occurs (indicated by a plus symbol, "+"). Each electrode may become either the anode or the cathode depending on the direction of current through the cell. A bipolar electrode is an electrode that functions as the anode of one cell and the cathode of another cell. A primary cell is a special type of electrochemical cell in which the
Silver chloride electrode bond with silver of the electrode resulting in silver chloride and free electrons to deliver to the lead wire. The reaction allows current to pass from electrolyte to electrode and the electron current passes through the lead wire for the instrument to read. When there is an uneven distribution of cations and anions, there will be a small voltage called "half-cell potential" associated with the current. In the DC system that is used by the ECG and EEG instruments, the difference between the half-cell potential and the zero potential is shown as DC offset which is an undesirable characteristic. Silver/silver