The plots of AE RMS voltage as a function of time indicate different stages of hydrogen absorption involved during charging process. AE signals observed at the initial stages are attributed to be due to the surface activation and initiation of hydrogen absorption. AE activity increases with time and saturates upon completion of hydrogen absorption. The major source of AE is the release of hydrogen bubbles at the surface of the specimens. The AE activity arising due to bubbles, increases as the specimen absorbs hydrogen and becomes constant when the specimen is saturated with hydrogen. The specimens were allowed to disturb hydrogen under a concentration gradient in the same electrochemical cell and the AE parameters were recorded again. The AE RMS voltage decreases steadily and saturates with time. Continued desorption of the hydrogen from the specimen is indicated by a decrease in AE RMS voltage with time, which ceases when all the hydrogen is disturbed completely. The hydrogen concentration was estimated from the "diffusion current transient" recorded simultaneously along with AE parameters during the discharging cycle. It has been observed from these investigations that the variations in the AE RMS voltage with time could be correlated to the residual hydrogen concentration present in the metal at any instant.