Electrode electrode. In a vacuum tube or a semiconductor having polarity (diodes, electrolytic capacitors) the anode is the positive (+) electrode and the cathode the negative (−). The electrons enter the device through the cathode and exit the device through the anode. Many devices have other electrodes to control operation, e.g., base, gate, control grid. In a three-electrode cell, a counter electrode, also called an auxiliary electrode, is used only to make a connection to the electrolyte so that a current can be applied to the working electrode. The counter electrode is usually made of an inert material, such as a
Silver chloride electrode chloride is a popular choice of biological electrodes due to its low half-cell potential of approximately 220 mV and the lower of the impedance of the electrode by silver chloride. When appropriately constructed, the silver chloride electrode can be used up to 300 °C. The standard potential (i.e., the potential when the chloride activity is 1 mol/kg) of the silver chloride electrode is a function of temperature as follows: Bard et al. give the following correlations for the standard potential of the silver chloride electrode between 0 and 95°C as a function of temperature (where t is temperature in °C):