Jeff wrote:

Hi,
Im confused regarding the choice of iron powder toroid for a 7Mhz high pass
filter. I need to use a small size (T68) toroid. For the freq range, some
reference texts say T68-2 is the one, others say T68-6" grade. I see
differing "best Q range" specs for the 6
grade.....2-30Mhz......10-50Mhz...etc.
Have similar need for 20Mhz LPF, but assume "6" is really the choice there.
Any suggestions as to the relative differences and reasons to choose between
grades 2 and 6 for the HPF in T68 size?

Having just been playing with Micrometals cores myself, I gather that -2 is
indeed the 'best' for higher frequencies.

The local distributor says it's stocked in greater depth too.

Have you also looked at Magnetics Inc and Arnold ?

Graham