DIYHiFi.org

Seems like a simple query, but online tools/calculators/charts give different answers by a factor of 10.

(Both Rs are same value. Taken from a UK aftermarket regulator PCB)
I read: Brn-Blk-Blk-Brn-Brn

Tool:
http://samengstrom.com/nxl/3660/4_band_ ... ge.en.html
Use, 5-band (I think!):
http://samengstrom.com/nxl/10116/5_band ... ge.en.html
Yields: 1K 1%

Chart:
http://personal.ee.surrey.ac.uk/Persona ... r_code.gif
Yields: 100R 1%

So which, if any, is it?!

Well, it took me a minute that I"ll never get back but wtf... you'll kick yourself for this one.

Answer: They're all correct. You screwed your interpretation of the Leon Audio Company Resistor Colour Code Chart, likely because they were knobs and changed it ever so slightly from what you'd expect to see or are familiar with... leading one to assume. It's like when you read your mind ignores or takes for granted a large number of things so you end up blind to them.

Look closely at the "multiplier" column, they dumbed it down to "number of zeros".

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'I am... everything is... changed... they're calling... your face... interwoven... who is...

I always measure to be sure.

The final brown band indicates a 1% resistor, which these days can be had for under a penny. (You don't even have to go to China for that price!)

A 1% resistor will have three significant digits, followed by the multiplier. The easiest way to think of the multiplier is the number of zeroes after the significant digits. Hence 1-0-0-1 will be 1.00 kohms.

Those zeros become significant themselves at that tolerance, but do you really need a simplification for base 10 multiplier? As we see here it does more harm than good.

BTW, what happens if the multiplier band is gold or silver.

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'I am... everything is... changed... they're calling... your face... interwoven... who is...

I don't have this PCB -- I'm trying to work (reverse engineer the ckt!) from the image posted on a web site.

Brutal. You can't trust those colors exactly, they often don't look like what they are, particularly on a blue background or with conformal coatings etc.

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'I am... everything is... changed... they're calling... your face... interwoven... who is...

Yeah, you're right. Big-time egg on my face here!

You have a point...
FYI, it's from a tracking pre-regulator -- an LM317 "upgrade" replacement module (based on the one in the Natonal datasheet). Here's the whole PCB from this site:

It's an old trick, I can't imagine they've done anything innovative with it.

Page 20:
http://www.national.com/ds/LM/LM117.pdf

Figure 5:
http://www.rose-hulman.edu/~herniter/Da ... 317-TI.pdf

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'I am... everything is... changed... they're calling... your face... interwoven... who is...

Yeah, nothin' new: the TPR is in the National datasheet, too. Same R values.
I've been using TPR for various 5 - 15VDC apps, but recently ran into issues when implementing it in a +/- 30VDC project. The issues being: Vout (i.e. DC voltage) fluctuates by a few mV with no load (haven't tested with load, but plain ol' humble 3x7, also w/no load, is tight). Also, for the 30VDC TPR, I get a slightly higher AC ripple than plain ol' single 3x7. Don't have these issues with TPR at lower voltages (e.g., 5, 15).
So that's one reason why I'm curious about the commercialized product above -- which does tweak the datasheet design from the looks of things. How did they tweak the TPR for stability at "higher" (~30) voltages? They claim 12-33VDC in their specs.

That trimpot could be vertical, no??!
It's a question of safety.
They should know that someone will power that up an stick a metal screwdriver to adjust the voltage.

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein

Not sure that trimpot model (=value desired, which is 10K) is avail w/top adj. (Murata?)?

Reminds me of the blue background skies in the various Mars-mission images before they corrected them. Ya know, like the "face" on Mars... The conspiracy theorist in me thinks: the space agencies may deliberately leak false-color images out to "wow" the stupid masses -- keep them tax $'s rollin' in. Then for the sake of science, they'll automagically publish corrections a few mos later... to justify high-paying jobs and keep pet programs afloat.
http://mars-news.de/color/blue.html
http://www.donaldedavis.com/PARTS/MARSCLRS.html
http://www.badastronomy.com/bad/misc/ho ... olors.html

Of course, the pocket industry of paranormal freaks (X-file fans, etc. -- the confabulatory conspiracy theorists) put out pseudo-sci garbage about the "real" (=Earth-like) Martian hues along with "Faces" and Chariots of the Gods!

Bourns, for instance.
It's pretty standard stuff.

_________________
Carlos Filipe

"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius - and a lot of courage - to move in the opposite direction." Albert Einstein