# Waht size is this capacitor?

Discussion in 'General Electronics Chat' started by rougie, Dec 5, 2012.

1. ### rougie Thread Starter AAC Fanatic!

Dec 11, 2006
410
2
Hello,

I always have trouble reading the values of small tantalum capacitors.

On the capacitor it clearly say: "u47 35"

But when I measure it with a multi meter it reads 485nano farad???

So what is the real value of such a capacitor...

thanks!
r

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2. ### #12 Expert

Nov 30, 2010
18,093
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It's pretending to be 47uf at 35 volts, and it's way too big to be 47nf, so I would have to assume it's broken.

3. ### DerStrom8 Well-Known Member

Feb 20, 2011
2,424
1,356
#12, I think the 'u' coming before the 47 is symbolizing 0.47μF, which is equal to 470nF. The 'u' just symbolizes a package type, tolerance, or manufacturer (not sure which in this case). I think it's a 0.47μF, 35 volt capacitor, and the measurements seem to support that conclusion.

Best wishes,
Matt

4. ### rougie Thread Starter AAC Fanatic!

Dec 11, 2006
410
2
ah yes! this makes sense... I don't why they can't just add a "." in front of the 47???

Thanks so much guys... your help is appreciated!
r

5. ### #12 Expert

Nov 30, 2010
18,093
9,683
Like my signature says, sometimes I'm wrong.
But from the size, I'd expect 4.7 uf, not .47 uf.
Oh well. We all get fooled once in a while.

6. ### bountyhunter Well-Known Member

Sep 7, 2009
2,498
510
correct. The location of the letter is where the decimal goes. For example a "2R2" resistor is 2.2 Ohms. A "2K2" would be a 2.2K resistor.

7. ### bountyhunter Well-Known Member

Sep 7, 2009
2,498
510
Because a decimal dot is tiny. It's very hard to see and easily gets rubbed off. That's why they use the letter in place of the decimal.

8. ### DerStrom8 Well-Known Member

Feb 20, 2011
2,424
1,356
I meant no offense, #12. I could very well be wrong as well.

I have had students use those types of capacitors in their lab experiments here, and I have put together their "kits". Most of the ones I've handed out have been 1μF or below, which is what made me wonder if that's what it was.

Best wishes,
Matt

9. ### bountyhunter Well-Known Member

Sep 7, 2009
2,498
510
It's a solid Tantalum, it's hard to predict value from size.

10. ### #12 Expert

Nov 30, 2010
18,093
9,683
No ruffled feathers here. Just taking responsibility for putting up a dubious answer. The other option is to let it stand and have people wonder if I still believe it's right. Better to be clear about it.

DerStrom8 likes this.
11. ### MrChips Moderator

Oct 2, 2009
17,567
5,450
It is most definitely 0.47μF or 470nF as confirmed by the meter.

We discussed this in a previous thread. The μ takes the place of the decimal point because the "dot" is easily missed in a photocopier, scanner or fax, besides other places.

12. ### rougie Thread Starter AAC Fanatic!

Dec 11, 2006
410
2
Its rare I use capacitors for other than power rail filters. In this case I did an RC circuit and that particular cap did the job. So I think too that it is a 0.47uF... now that you guys have brought up good points.