Why blue resistors?

It is a part of an implicit ad: the resistors are true blue!

"Harold kemp"

And why?

BTW

Maybe you have marginal colour vision.

..... Phil

drive

What, you mean as in "True Blue Aussie"?

or John Williamson's composition "True Blue"

(There are also 1% wirewounds although these tend to have numbers and not stripes printed on them, and they don't show up in consumer equipment so often, so I'm going to assume you're not talking about them.)

I used to believe that the blue coloring was somehow related to flameproof ratings (and in consumer equipment metal film resistors are commonly used where flameproof ratings are required by electrical code) but this is just a guess of mine.

Certainly there are also a lot of metal film resistors with a brown or even reddish color (I'm thinking of Vishay PR01/PR02/PR03). I much prefer the pale blue body because none of the color stripes come close to that color (blue and purple stripes are much darker); I have a much harder time distinguishing red vs. brown (or red vs. brown vs. black) on the brown and red-bodied resistors especially in poor lighting.

Doesn't matter much anyways, since almost everything new is surface- mount with tiny white lettering that I cannot distinguish white from black with! (To be fair some of the parts are laser-etched, so it's really just a different reflectance of black... no wonder I can't read it!)

Tim.

Most of the axial ones I get are grey, though some are blue. But the SM ones are all charcoal black, with the little confusing numbers on - like (when they aren't just a manufacturer's code) 470 means 47 ohms, not 470 ohms.

But 0.1% S&M resistors come in a variety of entertaining colours.

Paul Burke

I think it is to help hide the black when you over-current them.

-mpm

The numbers just replace the color code bands. It's 47*10^0.

Iwo

Yep. I can't see the difference between orange & red & brown, and blue & green on them. And Purple - don't get me started on purple. (I refuse to call it violet on those ()^# blue resistors.) And Yellow - what the hell is it - yellow, white, silver, grey, gold? Some designer color? Maybe if I used a magnifier... but dammit I can read a 1/8th watt carbon just fine.

Ed

They do indeed, it's just that the figures leave one expecting something different, more to the point when a 4700- marked resistor is 470 ohms. And why don't SM caps have any markings at all?

Yes, I always resort to my DVM. I suspect the whole thing is a conspiracy to sell more of these.

Or, it's a sinister plan to save a buck by gradually fading out the colors entirely. Afterall, who is going to object, if you can't read them anyway?

I vote for white with flourescent colors. Until then, it's back to 5%. Thoughtless manufacturers take note.

Harold K.

It's in keeping with surface mount resistors, where 1% resistors have

Some do, if you know where and how to look. A two character code identifies the capacitance. There is a Javascript calculator on one of my websites that will decode the values for you:

Michael, the link appears to be broken here. I think there's a list on the Vishay site.

Regards Ian

I copied and pasted it to the message while I was looking at it. What browser are you using? Recently the Earthlink server is slow as crap, and doesn't seem to want to work with anything except IE. Hopefully, I'll have a better host in a couple weeks.

I am creating a set of these tools for people who aren't technical, like assemblers or parts room workers. I also have some for those confusing old three or six dot military caps for the antique radio group.

I'm using IE6. The link still says "page not found", but if I go up one level I can see the file.

Regards Ian

You have to flush your "temporary internet files" if you hit a page that the IE can't find.