Ther is Not all the magnetic flux generated by ac current excitation on the primary side follows the magnetic circuit and link with the secondary winding. The flux linkage between two windings or parts of the same winding is never complete. Some flux leaks from the core and returns to the air, winding layers, and insulator layers; thus, these flux causes imperfect coupling. The energy associated with leakage inductance can be calculated according to analytical MMF distribution and energy distribution. From the differential volume of each turn is therefore, the total energy is the sum of the energy stored in each elementary layer, which can be given by where lw is the length of each turn, bw is the width of each turn, and h represents the thickness of each winding layer. Understanding Members’ Attachment to Social Networking Sites: An Empirical Investigation of Three Theories The thickness dx is situated at a distance x from the inner surface of conductor. The field strength H depends on the number of ampere turns linked by the leak flux path. Since the flux rapidly disperses on leaving the winding, the associated energy is much reduced, and the reluctance of the path within the magnetic core can be ignored, compared with that of the path in the windings; thus, the flux path can be expressed by the width bw rather than the full closed flux path According Understanding Members’ Attachment to Social Networking Sites: An Empirical Investigation of Three Theories to for where are the lay thicknesses of the primary and the secondary, respectively, and hΔ is the height of the insulator layer. However, as for fully interleaving arrangement in with the same approach, leakage inductance can be deduced as follows: Apparently, the fully interleaving arrangement provides a significant advantage in reducing leakage inductance. As a conclusion, aside from winding structures, leakage inductance in PT can be changed by adjusting some physical parameters, including conductor thickness and its width, insulator thickness, and the number of turns. As a parasitic element exists in transformers, the leakage inductance causes the main switch current at the device input to vary at a low slope between zero and the rated value and reduces the rate of commutation between the output diodes. In addition, the stored energy in the leakage inductance leads to a generation of voltage spikes on the main switch, which, aside from creating electromagnetic interference EMI problems, increases the switching losses and lowers the efficiency. Understanding Members’ Attachment to Social Networking Sites: Understanding Members’ Attachment to Social Networking Sites: An Empirical Investigation of Three Theories An Empirical Investigation of Three Theories However, in some applications such as a phase-shift-modulated soft-switching dc/dc converter, the magnitude of leakage inductance determines the achievable load range under zero-voltage-switching operation, and a relatively large leakage Understanding Members’ Attachment to Social Networking Sites: An Empirical Investigation of Three Theories inductance is desirable. In order to avoid an additional magnetic component, a leakage layer with low permeability has been inserted between the primary and the secondary to form a resonant inductor Stray capacitance in designing PT cannot be ignored. The potential between turns, between winding layers, and between windings and core create this parasitic element. In most papers about optimizing PT, the main Understanding Members’ Attachment to Social Networking Sites: An Empirical Investigation of Three Theories purpose is to reduce leakage inductances, but stray capacitances have not seriously been considered.