To design a portable low cost Cranial Electrotherapy Stimulator (CES) and to study the corresponding brain activity electrically. The designed stimulator was used as an external trigger and the impact was analyzed using 20 lead EEG electrode system with standard recording protocol. Subjects were tested under this and their corresponding normal and varying EEG with CES were noted. Result showed appreciable variation in the EEG signal when CES evoking potential was connected. The test was carried out for normal subjects in a selected age group. This test should also be done with huge population of diverse age groups and also for abnormal subjects. The results also confirm that this CES could be used in treatment for therapeutic reasons like anxiety, depression, insomnia, and chemical dependency.