E-type ferrite cores from TDK


Inductive elements are an important component of electronic and electrical circuits, especially in power electronics applications. The process of energy conversion in power electronics devices requires the use of transformers, which are often the largest and heaviest elements of the entire device. Transformers also have a significant impact on the entire conversion process and its efficiency, as well as determine the weight and price of the device. Therefore, the choice of the type of transformer and its core is a crucial step in the design.

The most popular type of core is type E (in Russian terminology, W-shaped type) and its varieties, which is determined by its shape, the convenience of winding the coil and assembling the finished transformer EE or EI type. In TDK products, depending on the size and presence of an air gap, the following popular series B6630 , B6631 , B6632 of E type ferrite cores can be distinguished. TDK's entire product line of E-type ferrite cores is defined by core dimensions ranging from E5 (5mm long) to E100/60/28 (100mm long). In addition to the overall dimensions, the determining factors for E-type cores are the effective magnetic path length I e , the effective magnetic cross section A e , the effective magnetic permeability µ e and the inductance factor A L .

Appearance of E type ferrite core Appearance of E type ferrite core

Preferred materials for E-type cores are SIFERRIT N27, N87, N97, N88, N95, N96, N92, T46 and N30. Ferrite N27 is recommended for use in switching converters up to about 100 kHz, and ferrites N87, N97, N88, N95, N96 and N92 for frequencies up to 500 kHz.

A range of E-type cores is available both without an air gap and with an air gap of various sizes (in the middle leg of the core). The need for an air gap and its value are determined in the process of calculating the transformer, since the gap changes the magnetic resistance of the circuit to the flow of magnetic flux in the core and makes the core inductance independent of the permeability of the material (lowers and stabilizes it), also affecting the hysteresis loop:

Influence of the air gap on the hysteresis loop Influence of the air gap on the hysteresis loop

For a number of E-type cores, additional accessories are also available - a coil frame for winding transformer windings and leads for desoldering on a printed circuit board, as well as mounting brackets. For example, for the E20/10/6 core, our product range includes a coil frame and brackets from the B66206 series. Thus, TDK offers a set of accessories for the most popular types of cores for the assembly of transformers of different overall dimensions with E-type cores, thereby simplifying the process of their manufacture and assembly.

Transformer Assembly Diagram with Type E Core Transformer Assembly Diagram with Type E Core

For more detailed specifications of TDK's E-type ferrite cores, see Specifications on the product page.