Martin Latecka wrote:
>Anyone have an idea on how I can measure capacitance?
>I wanted to charge a cap with a constant current and measure
>the time it takes to reach Vref. I have some _serious_ doubts
>about this though.
Your principle is good for any reasonabable size capacitors ( 100pF - 10000 uF)
Keep the curent generator constant at normal measuring tempereatures.
If you want more precision, add also low reference and measure dT/dV

>How do commercial meters work then?

My company manufactures high power capacitor meters and they put voltage to
capacitor and measure current, so it basically is impedance meter.
  C= 2*pi*f*i/V.
 The speciality of my meter is: it can find one faulty capacitor from many
parallel capacitors. By the way big capacitor bank is 300 meters long and
they have 10000 pcs 70 kg capacitors in 500kV potential.

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