RESISTOR value

[Speedy Builder5Participant @speedybuilder5]

Is this Black red black black Brown  or Brown black black red  Black  (the last colour being the tolerance)  So how do you know which end to start from ?

[peter1972Participant @peter1972]

The tolerance band has more spacing.

[Andrew TinsleyParticipant @andrewtinsley63637]

Not wishing to sound cynical, but cheap multi meters can be had for peanuts. maybe for 5 or 6 euros, well worth getting. Oh and the cheap ones are supposed to be dodgy on mains voltage according to some.

Andrew.

[John PurdyParticipant @johnpurdy78347]

It might be just the picture but it looks to me like it is Brown, Red, Black, Black, Brown. Which would be 120 ohms 1% tolerance.  The last brown band indicating 1% tolerance.  No resistor colour code banding that I am aware of starts with a black band. (I stand to be corrected!)

John

[Speedy Builder5Participant @speedybuilder5]

Andrew, I am working from the photo and so can’t measure the resistance and I am 700 miles away from the project which doesn’t help.

Bob

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, I guess it’s 120 ohms, judging by the one in the photo below. Both outside bands are brown by the way.

Regards Nick.

[John Purdy]

On John Purdy Said:

It might be just the picture but it looks to me like it is Brown, Red, Black, Black, Brown. Which would be 120 ohms 1% tolerance.  The last brown band indicating 1% tolerance.  No resistor colour code banding that I am aware of starts with a black band. (I stand to be corrected!)

John

You are correct, John

In the cold light of day … My iPad clearly shows

Brown, Red, Black, Black, Brown.

MichaelG.

[Speedy Builder5]

On Speedy Builder5 Said:

Andrew, I am working from the photo and so can’t measure the resistance and I am 700 miles away from the project which doesn’t help.

Bob

Andrew still has the right answer.   You can’t trust this component!  The colour code is ambiguous and can be read either way round.  As Peter1972 says the tolerance band should be more widely spaced at the far end, but I wouldn’t bet the farm on this example.  It’s either

• Brown Red Black Black Brown  :  1 2 0 0 1 = 120Ω tolerance 1%, OR
• Brown Black Black Red Brown  :  1 0 0 2 1 = 10,000Ω tolerance 1%

You can sometimes tell which reading is wrong if the colour code generates a value outside the E-series range. Not  here because 120 and 10k are both valid.

I have many of these plus some very similar inductors.   As well as being spaced ambiguously, the band colours don’t show well against the blue body. And my eyesight isn’t as sharp as it was.   It’s possible to get the numbers wrong AND to read the code backwards.  Doubly dangerous with a photo unless the screen is colour calibrated.  And completely wrong if the component is an inductor!

Options:

• Tell whoever is building the project to buy a multimeter so they can test the resistor.  (Only incurable optimists do electronics without a multimeter!)
• Send a known value resistor or have them order one locally.
• Tell them to suck it and see. Depends on the circuit, but safe enough if it requires 120Ω.  Then substituting 10k will stop it working without damage.  Not the other way round – substituting 120Ω for 10000 could result in magic smoke!   If the project blows up, they’ll understand the value of owning a multimeter!  And that risk can be assessed by understanding the circuit.

Not due to careless Asiatics flooding the world with inferior goods. My junkbox has several western made examples, old and new.  Examples include identical resistors and capacitors painted pink and marked with a meaningless code number.  It’s because they’re often marked for stock control purposes, not to help hobbyists!   Getting worse too – sub-miniature components are too small to colour code.

Dave

 

 

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Dave, here is a 1k and a 10k five band resistors. The one in the O/P’s post has a gap between the brown and black at the bottom, that is bigger than between the brown and red at the top, just like the 150 one in my photo above, and the two below with the red band.

Just to add, the first three colours denote the digit, the fourth colour is the multiplier, and the fifth is the tolerance, i.e. Brown, red and black = 120, and the second black = x 1, the final brown = 1% tolerance.

Regards Nick.

[Speedy Builder5Participant @speedybuilder5]

Thanks for those enlightening comments, So for the sake of documentation, I could say use a resistor between pin A0 and row 25.  I just love electronics!

Bob

[Nicholas Farr]

On Nicholas Farr Said:

Hi Dave, here is a 1k and a 10k five band resistors. The one in the O/P’s post has a gap between the brown and black at the bottom, that is bigger than between the brown and red at the top, just like the 150 one in my photo above, and the two below with the red band.

…

 

We’re not quite on the same page Nick!  Speedy asked about an ambiguously marked component, whereas your examples are crystal clear!

Difficult to read colour codes aren’t uncommon.  What value is this resistor?

More!  Not all resistors space colour code bands in the same way.  No ambiguity in the next example but note the spacing doesn’t follow the usual method.

My advice is simply this: measure components if the marking isn’t immediately obvious.  Why take the risk when inadvertently installing the wrong component can cause misery!   There’s no need to rely on the colour code.  Multimeters are cheap, not like buying an Avo when they cost a skilled man 2 weeks wages.

Dave

 

 

 

 

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Dave, no disrespect to your opinion, but I think I’ve answered the question, which was which end to start with. Peter1972 had already stated that the tolerance band has a wider space between it and the next band to it. Speedy’s photo looks clear enough to me, and as one can see, the two wired end caps are the same size, and the brown band on the lower cap, is clearly central, whereas the brown band on the top cap is on the edge of the inner side of the cap. I don’t know about anyone else, but I can see the bottom brown band is further away from the black band, than the top brown band is away from the red band, and so you should read the brown, red, and the two blacks first in that order, and the the brown tolerance band last.

Regards Nick.

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