Electrical conduction in the body is ionic.
• Electrical conduction in instrumentation circuits (and
wires) is electronic.
• Electrodes provide transduction between ionic and
electronic conduction.
• Electrodes are fundamentally an electrochemical
interface in which charge is transferred between
electrons and ions through oxidation-reduction
(redox) reactions.
• Electrodes function as transducers: They provide
both sensing and actuation.