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Written capacitance units
The Greek letter mu (like a u but with a tail starting the letter) is the correct symbol for micro which means millionth.
Mu isn't available on many keyboards so m is sometimes used instead. This can be confusing though as m is used in the SI system for milli, which is a thousandth, and there is a capacitance unit of a millifarad although it's not often used. In older circuits you often see mmf which is not m for milli either but means million millionths of a farad, or pF picofarads as we know them now. In electronics it is safer to use the keyboard letter u for the Greek letter mu as it looks similar and can`t be confused with any other notation. The units are, 1 Farad (F) = 1000 milli Farad (mF  not generally used) = 1000 000 micro Farad (uF) = 1000 000 000 nano Farad (nF) = 1000 000 000 000 pico Farad (pF  old mmF) Some capacitor values may be marked in alternative ways such as a number followed by K being used to show thousands of pF (= number of nF). Most formulae use the full Farad, so convert the value for calculations. The units relate by thousands/thousandths so remembering their names, including milliFarads, is useful for this. Example, 10,000pF = 10nF = .01uF = .00001mF = .00000001F All we do is move the decimal point 3 places at a time. If doing a calculation (i.e. to find the impedance of the capacitor at a known frequency) the last value, expressed in Farads, would be the one to use Last edited by John Caswell; 1st November 2013 at 04:47 PM. 
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