
Octopart Pocket Electronics Reference PCB - sas
http://crowdsupply.com/octopart/octopart-pocket-electronics-reference-pcb
======
trafficlight
I bought a set of these a few weeks ago.

[https://www.tindie.com/products/NsN/pcb-color-sample-
set/?pt...](https://www.tindie.com/products/NsN/pcb-color-sample-
set/?pt=directsearch)

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DanBC
This is lovely.

One gentle suggestion for version 2 is conversions between pico, nano, and
micro farads, and the capacitor codes used for these. Because even though it's
easy to do it's still nice when you're feeling cognitively challenged to have
a cheet sheet.

~~~
sas
Thanks Dan! Maybe if this one goes well I'll get to do a sequel :)

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hpcorona
Hmmm, meybe i'm getting this wrong, but... Isn't a color code too basic to be
in a card in your pocket?

I mean, c'mon, i haven't used color codes since High School about 17 years ago
and i still remember how to decode them. It's not that hard.

i feel that consulting a table is more time consuming that knowing how to
decode it... Usually while working with prototyping you end up with lots of
resistors, and i can't see someone checking each one at the time against a
table to reveal it's value...

But maybe i'm getting it all wrong, someone?

~~~
fnordfnordfnord
If you're breadboarding a lot, or manually stuffing printed circuit boards, or
otherwise doing manual assembly in some way, you quickly learn to read most
common ranges of values on sight. Maybe some people like to keep a reminder
around for when you encounter weird values, or when troubleshooting.

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joe_bleau
Like the SM footprints, but I'm not sure I see the point of the resistor color
code chart these days (If I do spec a through hole resistor, 99% of the time
it'll be a 1%).

~~~
DanBC
Not sure I understand - Vishay[1] MRS25 resistors are 1% and use a colour
code.
([http://www.vishay.com/docs/28724/mrs16m25.pdf](http://www.vishay.com/docs/28724/mrs16m25.pdf))

They're generally pretty nice as resistors go. Do you spec better than that?

[1] I used these when they were Philips, which shows how long it is since I
was doing this stuff.

~~~
joe_bleau
The 1% series has an extra value band, which throws off their multiplier.
Example: 1k 5% is brown black red (gold), but 1k 1% is brown black black brown
(brown).

We do use a few 0.1% values in some cal equipment--about $1 each!

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trevyn
This is way better, too bad it's over. :(

[http://www.pozible.com/project/31806](http://www.pozible.com/project/31806)

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fnordfnordfnord
Does "Set of Reference PCBs" mean four for $32.00?

edit: nevermind, I scrolled down far enough to find it.

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VBprogrammer
I prefer using a multi-meter. That might be something to do with being colour-
blind though.

~~~
sliverstorm
That's a pain-in-the-butt way to find the one resistor you need in a pile of
fifty. Even though you are color-blind, that's just red and green, so you too
can say to yourself "blue, blue, I need two blue stripes..."

~~~
DanBC
That's a weird mis-characterisation of what it means to be colourblind. It's
one of the discriminations that's still legal in England - electronics
companies are allowed to not employ people with colourblindness because of the
lack of suitable 'reasonable adjustments' and the need to have colour vision
for a lot of electronic stuff.

Also, any resistors not in a pcb should be in a nice drawer with a neat label;
any resistor in a circuit could give misleading values when multimetered
because it's in a circuit.

~~~
sliverstorm
_That 's a weird mis-characterisation of what it means to be colourblind._

I thought male pattern colorblindness (far and away the most common type)
simply means the inability to distinguish green from red, not total lack of
color vision. Hence why I would expect you could still locate resistors with
blue bands.

 _any resistors not in a pcb should be in a nice drawer with a neat label_

"Should" being the operative word here. If that always happened, we wouldn't
have bothered to give resistors identifying marks.

~~~
DanBC
> If that always happened, we wouldn't have bothered to give resistors
> identifying marks.

Yes we would, because we need to know what that resistor is when it's in a
PCB. We can't measure it because it may be in parallel with other resistors.

> Hence why I would expect you could still locate resistors with blue bands.

Can you identify what the colours of this image should be? (Ignoring the
massive clue in the filename.) :-p

([https://en.wikipedia.org/wiki/File:Rainbow_Deuteranopia.svg](https://en.wikipedia.org/wiki/File:Rainbow_Deuteranopia.svg))

That's for a severe form of the most common form of color-blindnes.

([https://en.wikipedia.org/wiki/Color_blindness#Classification](https://en.wikipedia.org/wiki/Color_blindness#Classification))

~~~
sliverstorm
_Yes we would, because we need to know what that resistor is when it 's in a
PCB_

Why couldn't we just label the resistor with silkscreen? We already decided
labeling their drawer was better than labeling the resistor, so why not apply
the same to the PCB? Easier to read silkscreen than color bands anyway, right?

 _Can you identify what the colours of this image should be_

I said blue. Notice the blue is quite easy to spot in the image you linked. Of
course it would still be a pain to try to find the 10k resistors by color,
yes, I know that. But at least the color bands wouldn't be _totally_
worthless.

~~~
DanBC
> Why couldn't we just label the resistor with silkscreen? We already decided
> labeling their drawer was better than labeling the resistor, so why not
> apply the same to the PCB? Easier to read silkscreen than color bands
> anyway, right?

Some resistors are labelled with silkscreen. Those resistors are expensive 1%,
0.1%, or 0.01%.

For run of the mill resistors it's cheaper to use colour coding. Also, when
assembling a PCB it's good practice to keep the codes visible. That takes
extra time for human operators. I don't know how machines do it for
conventional components.

Labelling the PCB is important. There's a space marked R1, and a parts list
telling us what R1 should be. There's a resistor in that space. How do we know
what that resistor is? We read the color code, or the marking on the device.

There could have been a mistake at the resistor making factory, so we have a
goods-in inspector who does some checking of the goods coming into the
factory, and we buy from quality vendors and quality manufacturers. We hope
the ISO 900x accreditation means something; we hope the certificates of
conformity mean something.

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triplesec
It's fun, but I'm not sure what it's for as I can look up these things on the
internets if I forget. Is this just an executive engineer gadget?

~~~
fnordfnordfnord
It would be a good thing for my students to have in their kits. I try to get
them to make something similar for SMT footprints every year (to print out on
paper) with varying amounts of success. It is easy to get confused on
different size designations (QFP, TQFP especially), and there is not a lot of
utility in making people memorize stuff like this.

~~~
sliverstorm
Package types are not size designations. Pin count & pitch matter more than
QFP vs. TQFP, and the dimensions of one manufacturer's TQFP can easily be
different from an others, so the datasheet is key.

~~~
DanBC
Yes, for designing a product people must refer to a datasheet.

But when discussing things it's nice when someone can correctly say "TQFP", or
when they see a choice of two ICs and you say "It's the QFP one" and they can
pass that tube over.

