1% colour codes

Discussion in 'Electronic Design' started by Terry Pinnell, Nov 25, 2004.

1. Terry PinnellGuest

In all the years in this hobby, I suppose this is the first time I've
had to look closely at resistor colour codes. My latest parts order
included a few .125W 1% resistors. With glasses removed and peering
closely I see
10k: brown, black, black, red, brown
100k: brown, black, black, orange, brown

I'd instinctively looked for a splash of orange and yellow
respectively. Removed from their tape and mixed with my other stocks,
interpretation hardly seems intuitive. Deciding from which *end* to
read is hardly obvious for starters!

2. Tony WilliamsGuest

Yes, those crappy 4-band colour codes. They came in a
few years ago, not exactly easy to read. I'm afraid
you always have to have your DMM handy from now on Terry.

3. Leon HellerGuest

I've used 1% metal film resistors for years. I write the value on the tape,
and do the same with SM Rs and Cs. The brown ring (tolerance) should be
separated from the others.

Leon

4. Robert BaerGuest

Since one has one percent resistors, that means an *extra* significant
digit for the value.
So: 10K = 100*10^2 ohms @1% and 100K = 100*10^3 ohms @1% (note the
As far as which end to start from, if both ends are "1" (brown), then
there can be a problem.

5. Terry PinnellGuest

Most of my dabbling now uses breadboard, so I'll return a newly-used
(and shaped) resistor to the container, not the tape. The ideal would
be more containers of course, but not practical here.
I'll take a look later. Pretty darned hard to see anyway.

6. Terry PinnellGuest

Thanks, understand that. But my point is that it's poorly chosen
coding, because it's inconsistent with the 4-band system. I want
yellow to mean '100k-999k', etc.
As in this example. And I guess for most of my 1% resistors, which
tend to be 100, 1k, 10k, etc.

7. John DevereuxGuest

You could still get 1% in the 3 band codes, last time I looked... you
just had to choose the right manufacturer (rohm?).

All my new resistor purchases are surface mount now, so the problem
does not arise. (Except you need a magnifier to read them of course).

8. Paul BurkeGuest

Not so much the tolerance as the series. Once you get to E96, you need
the extra band for weirdy values like 15k4. I only use 1% these days, as
it saves stocking multiple ranges. Except of course where it's necessary
to use 0.1% or whatever.

Paul Burke

9. martin griffithGuest

Hi Terry
http://www.safepub.com/Catalog/General/eyemagn.htm#galilean system
The medical ones are EXPENSIVE!

(I need a pair)

martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

10. Terry PinnellGuest

Wow - 136USD! I'll struggle on a bit longer and spend the 73UKP on

Actually, although I'm very shortsighted, anything under about 6"
(15cm) away is sharp without my glasses. Groping for them again after
a spot of close-up soldering can be hazardous though!

11. Mike HarrisonGuest

I'm sure I read somewhere that one end band is supposed to be wider than the others to indicate
which way round - I think it's the tolerance band.

12. Pooh BearGuest

The extra digit makes those bands red and orange respectively.
The tolerance band should be separated from the value by a larger
distance.

Graham

13. Pooh BearGuest

I find this kind of thing quite useful.

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=272527&N=401

Keep a 5x and 7x handy.

Graham

14. Richard HenryGuest

I was at an electronics show a few years ago where a vendor of really small
surface mount parts was giving away 3x magnifiers. I also purchased a pair
of magnifier reading glasses at Walmart. The combination is good enough to
convince me that I don't want to try soldering those little beasties. Me
finger tremor is about two-three pins worth on the tightest-pitch ICs we
use.

15. Jim ThompsonGuest

[snip]
You're not drinking enough ;-)

...Jim Thompson

16. Rich GriseGuest

Ya took tha wordsh right outta my *hic* glash.

%-*
rCHI

17. Richard HenryGuest

Will that a) increase the tremor, b) decrease the tremor, or c) make me not

18. martin griffithGuest

It keeps the yooth of today partying all night, vodka to calm the
nerves, and caffine for the reciprocal

martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.

19. Paul BurkeGuest

They party all night because they are yoof, despite what they consume.
Just like we used to do on cheap cider and Party 7s, remember?

20. Terry GivenGuest

Recently I have been using smt resistors with codes on them - how the
hell do you figure "768" = 604 ohms, or "010" = 100k.

I made a clip up with some copper pipe hammered to form tweezers, and a
plastic clothespeg, and attached leads & banana plugs to it so I can
easily measure 0603 Rs and Cs.

OTOH film cannisters are great smt component holders.

Cheers
Terry