[net.analog] RF filtered fuse

karsh@geowhiz.UUCP (Bruce Karsh) (10/04/84)

Does anybody know whether anybody makes
a good RF filtered bulkhead mounted
line fuse holder?

We bring line AC into our enclosure through
a line filter.  (CDE APF300CEE)  But then
we have this fuse holder sticking out,
presumably radiating RF.

Of course, we could try putting some filtering
around the fuse holder itself.  But it seems
easier to just buy a filtered fuse holder.

We are working at about 50MHZ.

        Bruce Karsh

crs@lanl-a.UUCP (10/04/84)

I would normally reply by mail but lets see if we can set a good example
and get some activity going in this group.

I don't have a direct answer to your problem but two things that may
point to a solution:

1.  There is a publication called ITEM (Interference Technology Engineers'
    Master) that may be available in your library.  It is published by
    R & B Enterprises, Div of ROBAR Industries, Inc., 20 Clipper Road,
    West Conshohocken, PA  19428.  It is a collection of articles and
    advertisements relating to interference technology (published once
    per year & free to "qualified subscribers").

2.  I wonder if you really have a problem.  I vaguely remember something
    to the effect that a given aperture is only a problem is it is a
    significant fraction of a wavelength at the frequency in question.
    Since the wavelength at 50 MHz is about 6 metres, the opening for
    the fuse holder may well be small enough to be no problem.

Let me know if you find any information.

Charlie Sorsby
...!lanl-a!crs
      crs@lanl

crandell@ut-sally.UUCP (Jim Crandell) (10/05/84)

The point about the dimensions of the fuseholder is well taken, but
for those who prefer simple solutions, I have seen something that
may help, though it's not exactly what was requested.  Corcom (and
possibly others) make some filtered line input connectors with
integral fuseholders.  The only one I can cite offhand is the one
used in the Sun-2 monitor which appears to have the part number
``F1881''.  A Corcom representative can probably supply more
information.

-- 

    Jim Crandell, C. S. Dept., The University of Texas at Austin
               {ihnp4,seismo,ctvax}!ut-sally!crandell