The ER series Transformer Core design is derived from the original E-core and like ETD and EC cores, has a round centre pole and outer legs with a radius to accommodate round coil formers. This core is mainly used for power transformers. The round centre pole allows the use of thicker wires while the shorter turn length keeps the copper losses low. Planar ER core is very suitable to build small SMD or planar power and signal transformers.
(EN)
