Hi,

Today I went to the electronics store and bought some capacitors (well, I hope that is actually what I got ). Anyways, bigger ones have capacitance values written on them, but smaller ones only have some numbers like 103, 104 etc. Shop owner said that I could tell the capacitance from those numbers, but I don't really know how to do that.

Is there something like a datasheet that will tell me the capacitance from the values written on capacitors?

 

Those are capacitor codes.

 

Caps like that are indicated in picofarads. Your 103 is 10,000 pf or .01uf and the 104 is 100,000 pf or .1uf. First two positions are value and last position is multiplier or how many zeros follow the first two numbers. Example 105 is 1uf and 475 is 4.7uf.

 

Caps like that are indicated in picofarads.

That's the one fact to remember - picofarads. Then the printed digits are a lot like the 3-band resistor color code; two significant digits and a multiplier.

 

And if there are only 2 digits, it is just that value in picofarads. I.e. a 47pF cap will usually be labeled 47 instead of 470 and both would designate the same value.

Bob