Resistors

[LektroiD]

I know that resistors with a tan coloured body are standard carbon, and blue bodied resistors are metal film. But what about Dark Red, Green or Brown bodied resistors?

There are many colour code sites and calculators available, but none seem to mention the colour of the bodies, surely this bears some kind of meaning?

[Uncle Krunkus]

From my experience, it means nothing at all. You can get carbon in many different body colours, same for metal film.

[magman]

I found this site which gives some guidance

http://www.geocities.com/dsaproject/electronics/data_book/resistors.html

but as Uncle Knunkus effectively said, there is more of a convention than a standard for the colour of resistor bodies.

From my experience, I use the following as a guide only:

A tan body is normally Carbon Film (be careful, there are other carbon resistor variants, be specific), though higher wattage's may vary. These also normally have a moulded epoxy body.

A light blue body is Metal Film, though these can shade towards grey in some instances. Again, these are likely to have an epoxy moulded body.

A dark brown body is normally Carbon Composition. These are an older resistor design and normally lower tolerance (5% to 20%). This type also normally have a more cylindrical shape with sharper edges than a moulded resistor. I have had some Metal Oxide resistors with this type of body though, but this is more an exception than a rule.

Some higher power resistors can have grey and red/brown bodies, this can be confusing as these can be both Wirewound and Metal Film.

I've also had some precision resistors that have red bodies, but these normally have printed values rather than using colour coding.

For most synth construction Carbon Film is a good minimum and Metal Film is better - especially in Filters (they also normally have a better temperature stability). As the difference in cost is tending to be a lower proportion of the cost of building a synth module, I'm tending to stock up on Metal Film values, buying them in 100's as I find I need them for about a penny each.

Last but no means least, as has been mentioned on these forums before, you can also get some unscrupulous people who counterfeit resistors, painting Carbon Film resistors to look like more expensive Metal Film resistors (some suppliers on eBay in particular). You have been warned.

Hope that helps.

Regards

Magman

[Sebo]

Hi:
I normally see the tan, light brown 5% carbon, the light blue 1% metal film,
and the dark brown 2% metal film.
But also (really often) see brown, satin green, and white for 1% metal film,
and lately I see blue for 5% carbon (I usually fight with the shop guy because
is triying to sell them to me as 1% metal film).
I always look at the tolerance band and not at the colour of the body.

[urbanscallywag]

See the recent thread about the Chinese resistors that are sold as metal film and are blue but have the temperature coefficient of a carbon resistor.

[etaoin]