Biometrics is the branch of science that includes the measurement of physiological variable and parameters. Physiological parameters are blood pressure, velocity of blood flow, action potential of heat muscles, temperature, pH value of blood etc. Physiology explains the physical and chemical factors that are responsible for the origin, development and progression of life. Human physiology is concerned with the specific characteristics and mechanisms of human body that make it a human being.The origin of Bio-potentials, Biopotential Electrodes, Biological Amplifiers, ECG, EEG, EMG, PCG, EOG, lead system, and Recording Methods, Typical Wave forms and signal characteristics.The body generates their own monitoring signals which convey useful information about the function they represent. These signals are the bioelectric potential. Bioelectric potential are actually ionic voltage produced as a result of electrochemical activity of certain special type of cells.