Reading capacitors - How to?

[winterhunter]

Hi everyone,

I'm certainly asking a noob question, but I have no way to verify this, so here it goes...

I've bought a "kit" of 100 assorted capacitors, and I'm trying to sort them out, with moderate success. I've learnt that there are several types of notation...

272 means 2700 nF, so 2,7 nF, right? <---- typo, 272 = 2700 pF = 2,7 nF

10n stands for 10n

µ1?? 100 nF?
n15? 150 pF?
H2.7 025? (I guess it is 25V, but the H2.7 patrt eludes me since it is one hell of a big tantalum capacitor so I guess that 2,7 pF is ruled out).
Z3.3 025? (idem)
3.3t25? (the symbol between 3.3 and 25 looks like a very small "t" - again it looks like a beast to be only 3.3pF)

HEEELLLP!

 

[hentai]

272 means 2700 nF, so 2,7 nF, right?

10n stands for 10n

µ1?? 100 nF?
n15? 150 pF?

correct... 2700n=2.7u
For the other ones i'm pretty sure their value is in uF but it would be helpful if u put a picture to see the exact placement of the symbols.

 

[winterhunter]

I've tried to take some pics, but the numbers are just not lisible.

So I will "draw" them :

|____| |____|
/ H2.7\ / Z3.3 \
| 025 | | 025 |
\_____/ \_____/

BTW: my multimeter can't read reliably any capacitance under 100 pF, and I can't get any reading from these big beasts (so maybe they are 2.t pF and 3.3pF, but the are 3 mm spheres, with maybe 50 times the volume of the 15 pF one that are sitting right besides them on my bench).

sorry for my lousy ASCII art, looks better before the forum erases all the "unused" spaces ;-)

For the n15 one:
______
|###| <-- orange band
| n15|
|____|
| |
| |

 

[audioguru]

272 is 2700pF which is 2.7nF.
The different coloured bands on ceramic pf capacitors is their temperature co-efficient, which is how their value changes with temperature changes.

 

[RODALCO]

If you try to measure pF values with a capacitance, meter you need to bear this in mind,

The leads you connect to measure the capacitor value will already have capacitance between them which needs to be subtracted from the actual reading on the meter if you use a capacitance meter. This is especially apparent when the leads are in parrallel with each other.

This is certainly important for low nF and pF values.

You can try it out yourself if you have a capacitance meter and put it on pF range.

Put the test leads next to each other in parrallel, read the meter display.
Then put the test leads under a 90° angle, you will see a different reading.

 

[winterhunter]

@Rodalco:
I know about it. My multimeter (whose smallest scale is 20 nF and starts to really measure something starting at 68 pF) has a zero bias of 20 pF (the capacitance of the connector on the multimeter body -- measuring with leads introduces bigger mistakes).

 

[Dean Huster]

I have a lengthy article that I've written on reading capacitor values that will answer most, if not all, of your questions. Contact me via regular e-mail (click on my name, click on profile, and click on regular e-mail in the upper right corner) and I'll send you a copy. I'm pretty sure that I've posted the article here before (it doesn't show up in the thread listings at the bottom) and I hesitate to re-post the thing for fear of irritating folks with repeat material.

Dean

 

[AllVol]

Contact me via regular e-mail (click on my name, click on profile, and click on regular e-mail in the upper right corner) and I'll send you a copy. I'm Dean

Doing all that resulted in a message saying you opted out of receiving e-mails. Probably a good thing: you were about to get inundated with requests.

 

[Dean Huster]

OK. I didn't realize that even though I had my e-mail address entered in the profile, I forgot to check the "I want members to be able to send me wonderful e-mails." Now try it out!

Dean