Most EEG research seeks to understand the dynamic process in the brain that is the basis of physical and mental behavior. The Automatic detection of spectral components in EEG is an important tool in the diagnosis of mental activity. This paper discusses the method of analysing the EEG signals recorded during different conditions of sleep. The software was developed to identify the various frequency components of EEG using MATLAB software package. The software was successfully tested in children's EEG in normal and induced sleep as well as with certain disorders.