RM cores (rectangular module) are used for the design of inductors with low stray fields. Each RM coil consists of 2 RM cores, the coil, using single or multi-section coilformers which simultaneously adopt the function of soldering pin carriers, and two retaining clamps.
The use of RM cores in inductors is particularly advantageous to the user with regard to the high packing density possible on the pc board, with the additional benefit of low stray field due to the closed desgin, frequency selectivity and electrical stability.
The dimensions of RM cores are adjusted to the basic grid of pc boards, i.e. to the modular grid length of 2.54 mm. RM 6 thus means that the core with coilformer occupies a quadratic area of 6 x 6 x 2.54 mm².
The cores without a center hole are recommended for applications in power electronics, for example as transformers or flyback transformers in SMPS. Compared with those with a center hole, these cores have a higher effective magnetic cross-section and allow higher power ratings at a higher AL value.
In addition to the use of RM cores as power transformers, the main area of application is the design of frequency-selective components, especially in the form of filter coils with a high Q value and low noise wideband transformers for applications in the range of small excitations. RM cores with dimensions RM 6 are classified with the group of SMD components (surface mounted devices).
For applications where multilayer coils are used or where the core is mounted directly onto the pc board, planar RM cores with a drastically reduced height („low profile“) in comparison to conventional RM cores are available.