[Amps] Carbon film or metal oxide film resistors for low-power RF circuits?

[Jim Barber]

In lieu of a Truly Accurate impedance bridge, this sounds like a job for 
the old MFJ whatever-the-number analyzer. I just finished reading a 
long-winded paper that asserted that metal oxide had less inductance 
than carbon film which had less than metal film, but there's also 
material out there that disagrees.

Assuming the MFJ gadget is accurate to within a few ohms at 50mhz, it 
won't take much for me to do some sleuthing.

Thanks,
Jim, N7CXI

Bill, W6WRT wrote:
> ORIGINAL MESSAGE:
> 
> On Wed, 12 Aug 2009 13:06:41 -0700, Jim Barber <audioguy at charter.net> wrote:
> 
>> Looking for opinions, of course. I find myself replacing carbon 
>> composition units all the time, and was wondering if metal-oxide would 
>> be "better" than carbon-film for these purposes.
> 
> REPLY:
> 
> Either metal-film or metal-oxide resistors are significantly more stable than
> carbon comp. Their only possible disadvantage is that some values may exhibit
> more inductance than carbon because the film is sometimes trimmed in a spiral,
> creating a tiny inductor. It is very small but at UHF it may be significant.
> Just something to keep in mind. 
> 
> 73, Bill W6WRT
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