Resistor colour code

[bennybrc]

Hi
Would anyone be able to tell me what the resistor value is for a resistor?
It has a big orange band,a small orange band and a small yellow band

Thanks
Ben

[Station X]

330k

[Amraduk]

Hello Ben,

It's 330K.

1st band Orange = 3
2nd band Orange = 3
3rd band Yellow = x1000

So that gives 330,000 ohms which is 330 kilohms.

Regards,

Dave.

[bennybrc]

Thankyou so much!
There is another with a big orange band,a small white band and another small orange,what would that one be?
Sorry but im still learning about resistors!
Ben

[AC/HL]

http://nearbus.net/wiki/index.php?ti...olor_codes.jpg

Edit: http://www.sysrecon.com/resources/4-...de-calculator/

[bennybrc]

That is brilliant!!
Thankyou so much

[Radio Wrangler]

One note of caution, those resistors, especially high resistance ones like that one, have a reputation of going much higher in resistance over decades of time.

330,000 Ohms or 330 kilo-Ohms or 330k Ohms are different ways of saying that resistance, and that's the value you need if you intend to replace it.

That type of resistor is a ceramic tube with a carbon-loaded composition stuffed into it and a couple of metal ends with attached wires shoved in and held by cement. It is wise to use an Ohmmeter to measure them to check that they haven't drifted too far in value.

When new they were within about +/-20% of the value painted on them. If they had a silver band they were within +/-10% and a gold band meant +/-5%. These tolerances were achieved by measurement and selection at the resistor manufacturer. If you bought 20% resistors, you got them after the more accurate parts had been creamed-off for sale at a higher price.

Modern resistors are still available with 330k as one of the standard values. Tolerances of 5% and 1% are more usual. They've also got smaller. The laws of physics haven't changed, a resistor of the same value in the same circuit still dissipates the same amount of heat but modern resistors remain reliable running at greater temperatures. For use in vintage equipment it's usual to replace old resistors with modern ones having a higher power rating just to get a part with roughly the same body size and the same surface temperature.

A second reason for a larger power rating for a modern replacement is that modern resistors are made for low voltage transistor circuitry, and that you sometimes need to buy the larger part to get something rated to work at the voltages found in valve equipment.

David

[frankmcvey]

Benny,

There's a simple mnemonic to allow you to easily work out resistor values without resorting to an online calculator - we were taught it as part of our RAF apprenticeship. It isn't very politically correct, but it's very useful, and I still find myself using it most days.

Rather than risk offending some of the more sensitive souls, I've PM'd you.

If anyone else wants the info, PM me!

Cheers,

Frank

[turretslug]

The problem with most nmemonics (polite or otherwise) is distinguishing between the three 'B's and the two 'G's- Black, Brown and Blue, and Green and Grey- in the sequence. If frankmcvey's is the same as the one I'm aware of, it doesn't do this, as doesn't Bye, Bye, Rosie, Off, You, Go, Birmingham, Via, Great, Western.

Of course, to those of us who've spent many of their working days encountering resistor codes, reading values becomes instinctive and it can be hard to realise that it was once as baffling as any ancient language. It quickly establishes with practice and stays there, though.

Most of the colour code is the same as the rainbow, I twigged this when I was about 10, it's been easy after that time.

[Andrew B]

I use "Billy Brown Revives On Your Gin But Values Good Whisky"

[McMurdo]

When I was a nipper I found a 'radiospares' resistor calculator, one of those circular yellow ones with little wheels. Later I had a free cardboard one from someone like Cirkit or Marco Components. These are a great aid to the student to use until the colours are consigned to memory.

Today's equivalent would be an online calculator that caters for 5 and 6 band resistors too.

When I went for my first interview for an apprenticeship (at PYE Unicam) one of the tests (for colour vision) was to tell the colour bands of a few resistors, the first one was handed to me and I said 4k7 (yellow, violet, red). The HR chappie didn't understand so I converted the value in my head back to colours. Funny how the brain works.

[TonyDuell]

Back when Maplin sold a useful range of components, they once sold me 100 (each) of 2k2 and 33k 1/8W resistors in the same bag.

(For the uninitiated, 1/8W resistors are minute. The colour bands on those are red-red-red and orange-orange-orange respectively)

[pmmunro]

Spill a good assortment of random valued resistors on a bench then sort them by value. Repeat if necessary and the colour patterns are etched in the brain for life - until you meet a five band resistor.

PMM

[bennybrc]

Thanks for that!
Resistors have always been confusing for me
I bought the resistors i needed from maplin and guess what? They put them in the same bag!! Had to use my meter to find out which was which

[AC/HL]

It'll come in time, none of us were born with the knowledge.

A bit like riding a bike, once done never forgotten.

[TonyDuell]

Talking of the nmemonics for the colour code, the one I always remember (although you have to think of 7 as 'Mauve' is :

Better Buy Resistor Or Your Grid Bias May Go West

No possibility of forgetting what it rekates to, but like most others it doesn't distinguish clearly between the 3 'B's and the 2 'G's.

The more PC version of the very un-PC one (I will not post the latter publically, if you really can't work it out, PM me...) actually does help with the 'B's (but not the 'G's) :

Bad Boys Rape Our Young Girls But Violet Gives Willingly (Get Some Now)

Take the first vowel as well and :

BAd -- BlAck
BOys -- BrOwn
BUt -- BlUe

The 'Get Some Now' is of course Gold, Silver, None for 5%, 10% and 20% tolerance bands

[Herald1360]

Originally Posted by pmmunro

.......the colour patterns are etched in the brain for life - until you meet a five band resistor.

PMM

I still have think twice about five banders. And three times for anything under 100 ohms