Fwd: [AMPS] Globar Resistors

[Phil Clements]

> > >Dan Hearn, N5AR wrote:
> >
> >>I have been using these resistors (Globars) in parasitic suppressors for many
> >>years . Has anyone ever had one of these fail or change value without a
> >>change in external appearance?
> >Like you Dan, I've used the small Globars for years for parasitic
> >suppressors and now, more recently for glitch protection and never found
> >any problem whatsoever.  I also saw them in use for some commercial
> >multi-kW amps, by Create Eng., with the same units.
>
> A 6" long ''non-inductive'' Globar resistor has over 100nH.  One
> disadvantage to Globars is that the length to diameter ratio tends to be
> too high - typically about 6 or more to one.  The L/D ratio for a vhf
> suppressor resistor needs to be low - otherwise the desired
> stagger-tuning effect is not obtained.   Cesiwid/Globar/Kanthal can make
> such resistors on special orders of 1k minimum units.
> >
The  10 ohm globars that Eimac uses on their 4-1000A amps that I described earlier
are 2.5 inches long and .75 inches in diameter.  The 50 ohm units from SSN are
1.87 inches long, and .5 inches in diameter.

(((73)))
Phil, K5PC




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