Hal said:
>quickly saturated the cores, heated things up and made for squirrely
tuning,
The cores can get hot before they saturate, just by virtue of the energy
used moving the domains around the B-H curve.
I suspect that because of their permittivity, a high voltage on them can
lead to a capacitive displacement current through the ferrite, leading to
heating, too. Some of the 'lower loss' ferrites, meant for VHF
applications (e.g. ferrite rod antennas in pagers) can be very susceptible
to magnetic fields, driving them to a point on the B-H curve where they
lose properties. One place I worked about the time the Weller irons with
Curie point temperature control came in ruined a batch of 200 expensive LC
filters because of the magentic field of the newly provided Weller irons
on the production line affecting the ferrite!
Of cousre, the production people blamed engineering, and tried to charge
it against our budget!
73
Peter SM/G3RZP
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|