How to Select and Use Ferrite Cores
How to Select a Ferrite Core 3
Different ferrite materials
Different base materials for ferrites have varying impedances and different target frequencies. For this example; TRMH is made of a material that is effective at frequencies in the kHz range, TRM is made of a material that effective at frequencies around 1 MHz, and GTR is made of a material that is effective at frequencies around 10MHz and above.
|(1)||TRMH-16-8-16E||10000||Green (epoxy coating)|
|(2)||TRM-16-8-16E-WE||5000||Blue-Green (epoxy coating)|
|(3)||GTR-16-8-16||700||Black (no coating)|
Choosing a ferrite with the highest impedance at the problem frequency will have the most significant results. In situations where the problem frequency is above 200 MHz, it is more effective to use multiple ferrites with high impedance than it is to turn the cables. This is because while having a higher impedance, the frequency that the ferrite will target shifts to a lower wavelength once turned.