Technical Information

High Frequency Transformers Ferrite Core Range

The selection of the ferrite core type for a specific transformer depends on the design parameters and the designer’s personal preferences. The indicative power capacity for different core types (chart below) provides a general guideline for an initial core selection.

Power Capacity Chart

Power range (W)	*Core type using N67 grade material**
<5	RM4; P11/7; EF12.6; U10
5-10	E(F)16; RM5; P14/8
10-20	RM6; E(F)20; P18; U15; EFD15
20-50	RM8; P22; RM10 ETD29; E25; EFD20
50-100	ETD29; ETD34; RM12; P30; EFD25
100-200	ETD34; ETD39; ETD44; P36; E30; E42; EFD30
200-500	ETD44; ETD49; E55
>500	ETD54; ETD59; E65

Note: The power capacity of each core type varies due to differences in topology, operating frequency and temperature, flux density, and material grade.
* Siemens material grade

Ferrite Core Ranges

E cores and accessories		Range: E5 –E70
EFD cores and accessories		Range: EFD10 –EFD30
EP cores and accessories		Range: EP7 – EP20
ER cores and accessories		Range: E9.5 –ER54
ETD cores and accessories		Range: ETD29 –ETD59
P cores and accessories		Range: P 5.8 – P48
PQ cores and accessories		Range: PQ20 – PQ35
RM cores and accessories		Range: RM4 – RM14

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