The object of this paper is to make learners have study environment to study adaptively, anywhere, anyone, anytime and, just in time, not disturbed by time and place. So, it helps learners find solutions to questions and problems which they can face in the process of learning. This paper desires to find possibility of ontology which can solve problems after considering semantic web and theory of ontology by studying existing reference books. As ontology has the structure that can guess the data which is not showed clearly, so it can make the result more accurate and be the knowledge every learner sympathize and trust. I established the ontology frame about the electronic circuit which learners can solve their questions everywhere, anytime, and reconfirm what they studied, so I studied on application for e-learning based on ontology.