Recently, Somebody Somewhere wrote these words
> > Recently, Somebody Somewhere wrote these words
> >> Are those resistors carbon-composite types from the 1960's?
> >>
> >> In that case I wouldn't be so sure that you can eliminate them. We
> >> had couple of those in a student lab I was teaching. Every once in
> >> a while we found 5.6kohm devices with roughly 200ohms and/or vice
> >> versa.
> >>
> >> These were unused resistors which were still in their original
> >> package, not exposed to anything which might be considered harmful
> >> for a resistor during the 30+ years of their shelf life...
>
> > Being a complete lazy ass, I checked all these resistors with
> > Analogue Signature Analysis, using two flying probes with a variable
> > (frequency and magnitude) sinewave. The display shows Voltage on X
> > axis, and current on Y axis, so a reesistor looks like a diagonal
> > line. They came up pretty similar. It's not rocket science, but it
> > is testing under realistic conditions.
>
> > Anyhow, _I_ eliminated the resistors, I didn't take them for
> > granted.
>
>
> Hi Declan,
>
> I didn't test our broken, unused carbon-composites with a curve
> tracer, but they behaved like resistors even if broken. The only
> problem was that their resistance was more than a factor 10x off from
> the nominal value...
>
> Uwe.
I don't doubt your findings, Uwe.
The test I described would have caught 10% tolerance shift and alarmed
me at 20% off but it is strange if you haven't used ASA before. I have
used the same technique to match potentiometer settings from board to
board. You seem to be talking about ten times the value.
--
With best Regards,
Declan Moriarty.
--
Author: Declan Moriarty
INET: [EMAIL PROTECTED]
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