This paper introduces an energy-analysis of the flow of electrical charges and magnetic flux in addition to the flow of heat into a thermodynamic system. The analysis depends on the results of a held experiment on a magnet that attracted iron balls and a Faraday’s discovery as well as similarities between the laws characterizing the flow of electric charges, magnetic flux and heat. As the electric charge and magnetic flux produce entropy changes in some applications as magnetic hysteresis and capacitive deionization, we may express the electric charges and magnetic flux in terms of entropy changes times their corresponding potentials by analogy to expressing heat as a product of temperature and entropy changes. Introducing such postulates into the held energy-analysis; a new fundamental equation of thermodynamics that embraces the flow of electric charges and magnetic flux in terms of the electric and magnetic potentials was derived. The derived equation proved its truth in numerous studies of general energy interactions. Such postulates help also in defining the electric charge and magnetic flux as categories of electromagnetic waves of assigned electric or magnetic potentials and offer plausible explanations of newly discovered phenomena in the fields of electromagnetism and thermodynamics as Kerr effect and magnetic expansion