Can someone explain my ceramic capacitor values to me?

[thedarxide]

I've aquired a bag of various ceramics, and I'm having trouble figuring out the values...

One says n51, I assume that's 51nf?

Some say 91, underlined, what are they?

Some say 15k, what the hell does that mean?

Some say 27g...

Some say 0.5

Help!!

[bioroids]

Normaly the value on ceramics is given in picofarads, using three digits. The last of these digits is a multiplier which tells you how much zeroes you put to the right of the previous two digits. So if it says '101'  you know its 10 folowed by one zero, that is 100 picofarads. I there are only two digits, it means you have that value in picofarads, so the '91' cap is 91picofarads (91pF).

Sometimes they add characters too to indicate the voltage rating or thermal stuff, I am not very aware on that.

I never seen it on ceramics, but sometimes they use the character 'n' and 'u' as a way to show you the unit and where you put the decimal point. So n51 would really mean .51 and the n means nanofarads. So the n51 cap would be 0.51nF, or 510pf that's the same. I've seen this only on poliester caps, but I suspect this can work on ceramics too.

The other letters, I'm not pretty sure. The 'k' can be used as a temperature rating and also could be the multiplier for one thousand (so 15k would mean 15000pF, that's 15nF). I don't if this is the case.

Luck

Miguel

[twabelljr]

     Actually, the letter is usually the tolerance %. Read this:
http://xtronics.com/kits/ccode.htm

[bioroids]

Cool, very complete page.

Thanks

Miguel

[thedarxide]

ah, that's great guys, thanks.    So what's the barrel shaped one i've got that just says 0.5?  0.5pf?

This is what i get for ordering a lucky dip bag of ceramics.... 

[twabelljr]

    .5pF would be very small. But that is what most explanations would lead us to believe. There is nothing else printed on it? Barrel shapped caps are usually electrolytic, and they are usually in uF or F. Is it possible to post a picture of the mystery cap?

[thedarxide]

It's far too small to get a sharp shot of, that's definently all the text says, here's a bad pic:



I suppose i could hook it up and then work it out from the chargeup rate?

[twabelljr]

    Warning: This is only a guess!   My guess would be a .5uF axial leaded ceramic cap. Thumbing through a Mouser catalogue, seems that only SMD caps go as small as .5pF. Without a meter that measures capacitance, I don't know how to suggest measuring your cap's value. Maybe one of our forum experts will know. I'm curious to learn how myself. Best of luck, Tommy.

[phaeton]

ah, that's great guys, thanks.    So what's the barrel shaped one i've got that just says 0.5?  0.5pf?

This is what i get for ordering a lucky dip bag of ceramics.... 

Ha!  You got these from Jameco!

[thedarxide]

Nope, Maplin.



They were out of general component packs, and I've got nothing useful left at home, so I thought i'd buy a couple of lucky dip bags 

Won't be doing that again... the IC bag came with a german spec sheet, so i'm not even sure what half of them do, and the pots bag has got things i've never even seen in....

Will have to find a use for some of this stuff now 

Still, were very cheap...

[phaeton]

Ahh... had I known you were overseas I wouldn't have made such an accusation   (the term "lucky dip" should have clued me).


I did the same thing though- I bought a grab bag of mylar caps from Jameco some time back.  THey all just came in a heap in a single bag.  I looked at the numbers and letters on them and was "WTF?!?".  I figured it out and sorted them, but for a few of them I'm not 100% sure i'm reading some of them right.

I've even got some yellow axial-lead caps in the same size as you mention.  They look like skinny yellow crayons with really long leads.

[tiges_ tendres]

Ahh... had I known you were overseas I wouldn't have made such an accusation   (the term "lucky dip" should have clued me).


I did the same thing though- I bought a grab bag of mylar caps from Jameco some time back.  THey all just came in a heap in a single bag.  I looked at the numbers and letters on them and was "WTF?!?".  I figured it out and sorted them, but for a few of them I'm not 100% sure i'm reading some of them right.

I've even got some yellow axial-lead caps in the same size as you mention.  They look like skinny yellow crayons with really long leads.

I bought the same bag.  I prefer to spend a bit more and buy the specially selected ones, it works out cheaper in most cases than buying them same amounts individually.  It only sucks when you get a bunch that you cant use, like 0.0033 uf.

I quite like those axial mylar caps, they take up more space, but if thats what you need, in the words of Tim Gunn.  "Make it work!"

[phaeton]

I got a pile of .1uFs that are little hard white plastic boxes with short, thick leads.  They're toadilly awesome on the breadboard- they fit right in, lay close to the board and don't flop around.  I've looked around Jameco's site for something that would indicate this sort of 'package'.  I'd like to order up a huge mess of these in all the usual values just for breadboarding.

[KRK]

the IC bag came with a german spec sheet, so i'm not even sure what half of them do,

Try www.alldatasheet.com I've found them to be useful.

Cheers!