DESCRIPTION
of the “E” patterns Since “E” cores have two open coil sides, they provide substantial room to bring high current lead wires out from the coil. In the typical “E” lamination, the center leg (one of three legs) is twice the width of either outer leg. In theory, magnetic flux flowing out of the center leg divides equally and flows into the outer two "E" core legs. Since the outer legs handle half the flux they only need to have half the cross-section that the center leg has. It is easier to achieve high voltage electrical isolation with an “E” core than with a pot core. Presentation of EER-core and ETD-core EER-core and ETD-core are examples of type “E” cores with round center legs. The combined cross section of the two outer legs of EER cores and ETD cores should equal or exceed that of the center leg. The core stack is a stack of laminations and the typical stack has core legs of rectangular cross-section. Typically the inductor or transformer coil is placed over the center core leg.
