tempco of 5% carbon film resistors

[Harry Bissell]

IMHO (maybe not too "H") i don't use the carbon film resistors at all. There
are no advantages except cost. Carbon Composition resistors have very high
peak power ratings, which was good for circuits subject to severe use (like
Tubes...) They are also very low inductance.

Carbon films don't share these characteristics...They overload easily and have
some inductance.

Metal films are also subject to overload and have some inductance, but they
are very good in temperature stability, long term stability, and are usually
1%, which makes almost every circuit (at least opamps, diffamps, filters,
VCAs, VCOs etc) perform better. I even use them for pullups, etc, just so
someone doesn't make an assembly error and put a funky 5% where a nice stable
1% MF belongs...

Tube Mavens... look for Bulk Cermet resistors which are starting to come
out... they are Ideal as replacements for the old carbon comps and available
in higher wattages... Right now the selection of resistance values is limited.

Harry (resistance is futile...) Bissell :^)

macdonald at evenfall.com wrote:

> None of the catalogs that I order from listed the temperature coefficients
> of plain old 5% carbon film resistors so I went on a search to find out
> what they might be.
>
> Xicon says theirs are rated at 0 to -700 ppm per degree Celsius for
> resistor values from 100k to 1 meg.  Okay for many uses I guess but maybe
> not so great for trying to build a temperature stable VCO.
>
> Here's the link I used:
> http://www.xicon-passive.com/resistor.html
>
> click on the "CF" link to get the 5% carbon film PDF file.
>
> Hope this is useful or interesting for someone,
>
> -Chris MacDonald