disc capacitor value markings?

[sfr]

okay, i was walking by the radio shack in the strip mall by my parents house as i was swinging by the grocery store to get some cereal, and they had a bin of various electronic parts on clearance in the window so i grabbed some cheap opamps and jacks and switches and other misc. stuff, a whole bunch of parts for next to nothing.  

one of the things i picked up was one of those little blister packs of random disc capacitors.  but how the heck do you tell what the values are on these things?  

some of them have the three-digit-code plus a letter, which i understand as two value digits, the number of zeros, and a letter for a tolerance code - but what is the unit of measure?  I'm assuming pF, but i'm uncertain?

and what do you make out of one with just a two digit number, or a two digit number and some letters?  (both of these times, the two digits are underlined, is that important?  what about the little black cap on top of one of the caps?)  

the two i'm talking about there, one just says "10" and it's underlined, and one says "NPO   -  68K   -  KCK"  (inbetween the dashes being each line)

I guess this is the danger of being self-taught - i've been doing electronic tinkering for a very long while now, but i've always ordered my parts online so they come in the nice labeled baggies, and when repairing things, i've only needed to replace electrolytic caps so there's plenty of room to write info down.  i can't believe i never learned this, i feel kinda stupid.

[sirkut]

This has been a great reference for me for quite sometime:

http://www.electronics2000.co.uk/

there is even an application that you can download that will tell you what those 3 digit codes are if you ever need a quick check on the value. Does resistor color codes, etc. enjoy.

[bwanasonic]

You may find this handy:

http://www.electronics.vispa.co.uk/

You can find "Electronics Assistant" there, which is an all purpose tool for fiquring resistor/cap values, converting values and calculating equations with Ohm's law.

I think the *black spot* caps are high-voltage?

Kerry M

[AllyP]

No dice my friend!!!

The site seems to be down  Correct URL?

[keninverse]

it may be easier to read it with a multimeter...just my $0.02

I once read on synthdiy that radio shack buys the second-rate stuff from parts suppliers.  He spoke to a buyer while in some convention in Hong Kong and the buyer admitted this...