For the life of me... (capacitors)

[mth5044]

I can't figure out a good way to determine how to identify a capacitor by it's markings.

Sure, electros are find and dandy (I may be dumb, but not blind  ), but I've pulled out a project box that I started a bit ago and wanted to get it done. During this time, I was still ordering all my parts from small bear, so all the caps come in little neat baggies, but there is no way to tell them apart (ala mouser/digikeys labeling system). I can see the letterings, but when I google them (along with various other terms like capacitor), I get bubkis.

Is there a number/letter system that can be used to ID the caps? Sure, I could look at my small bear order and see how many of each I ordered, but there are some that are singles, or doubles, so it won't really help.

They are the panasonic poly film that smallbear sells, if that makes a difference.

Can someone shed some light?

[Jered]

  They don't have numbers like 104, 222, 471, etc. on them?

[mth5044]

Yeah sorry, by 'letterings' i meant the numbers and letters. They are on there, I just don't have a clue how to read them? Is there an easy way like resistor colors?

[frequencycentral]

104 = 0.1uf

473 = 0.047uf

103 = 0.01uf

472 = 0.0047uf

102 = 0.001uf

etc.

http://www.justradios.com/uFnFpF.html

[mdh]

It may be easier to remember how to read the markings if you know how they work.  They're just like the colored bands on 5% tolerance resistors -- the first two digits are read as numbers, and the third tells you how many zeros to tack on.  So, 104 = 10 0000 = 100,000.  These values are given in pF, so 100,000 pF = 100 nF = 0.1 uF.

[mth5044]

That is excellent! So they are always in picofarads then.

Great info, you guys are tops.

[eleanor296]

That is excellent! So they are always in picofarads then.

Great info, you guys are tops.

Yeah man... it ain't easy at first.
Took me a good while to get used to it.
But you'll learn quickly, once you start putting .01uF where a .1uF is supposed to go 
Trust me, I know from experience.

Best of luck!
Andy

[Fuzzy-Train]

This site is pretty helpful as well.

http://www.electronics2000.co.uk/calc/calccap.php

[Just1More]

I found this to be extremely useful:

http://www.olcircuits.com/documents/resistor_and_capacitor_charts.pdf

[davent]

Here's a chart of cap codes you can print out and keep handy.

http://www.amplates.com/images/AmplatesCapChart.pdf

dave

[newperson]

i like this one because the values go a little higher than normal. 
http://www.hamradio.cc/electronics/capacitance_conversion_chart.php

[MohiZ]

They're not even nearly always in picofarads. Especially polyester caps might have the number in plain microfarads (uF), here are a few examples from what I have:

1 K (=1 uF)
u1 (=0,1 uF)
0,47 (= 0,47 uF)
.033K (=0,033uF=33nF)

or in nanofarads, such as
2n2K (=2,2nF)
3n3 (=3,3nF)

You can usually tell whether the number is in picofarads or not, because a very small number in a physically not-so-tiny cap is usually in microfarads, unless it has that letter n after it (then it's in nanofarads).
There's also a bunch of other digits and letters for the voltage rating, etc. So don't be fooled!