[AMPS] Re:

[Rich Measures]

>........
>I measured an old 50 Ohm Carborundum style resistor last night. Sometimes
>they are called Globars. It is similar to those made by Cesiwid now. It is
>an 885 AS style, is 0.75 inches in diameter, and 2.5 inches long. The power
>rating of this part is 15 watts average, with 2500 Joule peak energy dumped
>in it, or 4 KV peak across it.
>
>Dc resistance was about 52 Ohms or so. Using the Hp 4815A vector impedance
>meter, i cranked it from 1 to 108 MHz. The magnitude stayed slightly over
>50 Ohms, and the phase angle only began to slip positive, about 2-4 degrees
>from zero, at 108 MHz. That says that this particular R is pretty damn good
>for a "non-inductive" power resistor, and might work nicely in a particular
>damping or suppressor application. 

-  The critical thing is the inductance of the suppressor resistor (Rs).  If Rs has nearly the same inductance as Ls, the stagger-tuning/broadbanding effect is lost.   My guess is that 15nH is about tops for building an effective VHF suppressor. 

>Sometime when I have one handy, I'd like
>to measure one of the bigger pieces.
>
Me too   
  €


cheers
Rich...

R. L. Measures, 805-386-3734, AG6K   


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