Resistor Colour Codes - What Am I Doing Wrong ?

johnny_t · 12 Apr 2006

Wanted some 3k3 Resistors so bought some from Maplin, and they were marked:

Orange, Orange, Black, Red, Red, which to my mind reads....

3 3 0 00 and then +/- 2%

which I would have thought was 33k. However, they insisted it was right (not that they filled me with much confidence, but it is about twenty years since I last had to work this sort of thing out) and I have checked with a meter and they are indeed 3k3, but I still can't work out why.

So, why ??

plugwash · 12 Apr 2006

at a guess you are reading brown as red, the two colors are quite close and if you don't have much experiance with reading color codes then its quite easy to read them wrong.

orange orange black brown (gap) brown would be 3K3 1% which sounds right by my knowlage of the maplin stock range. (i don't think maplin sell any 2% resistors)

johnny_t · 12 Apr 2006

Aha !!

Muchos Gracias !!

Diyisfun · 12 Apr 2006

So there could be a colour blind problem, have you had yours checked?. ps not trying to be smart.

plugwash · 13 Apr 2006

its possible though i think it quite unlikely, i've always passed color blindness tests and yet it took me quite a bit of time to learn to actually read the color codes reliablly.

the fact is some of the colors are very close, for example the browns can be redish and the reds can be dull, takes some experiance to tell where the boundry lies.

similarlly with orange and yellow it takes experiance to know just how much of a reddish tinge a yellow can have before its considered an orange.

reading the codes backwards is another problem especially with resistors that are both physically small and tight tollerance (with the wider tolerance resistors the silver/gold band is a dead giveaway to the order)

olly_k · 13 Apr 2006

I find resistors with blue bodies can appear to change the colour of poorer printed bands. Try under different light?

Qedelec · 13 Apr 2006

Have I entered the twilight zone or has no one thought to check the value with a meter, seems obvious to me.
And if you haven't got one, should you consider another career?

johnny_t · 13 Apr 2006

Yes - Hence the line in my original post "and I have checked with a meter and they are indeed 3k3"....

Diyisfun · 13 Apr 2006

johnny_t

diynot

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Resistor Colour Codes - What Am I Doing Wrong ?

Similar threads