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trailkeeper (November 30, 1999 at 12:00 am)
Hey coolbluelights, I think I have a method to calculate the value once its already made, see my comments here.
trailkeeper (November 30, 1999 at 12:00 am)
>I tried to "refigure" the formula method out:I dont have much equipment here to check it out but I think this might be it with the simple test circuit I described in my previous comments:Xc = Vc / Ic (can get Ic from Vr/r )then from:Xc = 1/((2pi)fC) we get:C = 1 /((2pi)fXc)Does anyone think this is right?
trailkeeper (November 30, 1999 at 12:00 am)
> from my last comment. I know you can get meters to measure capacitance and inductance, but this is the basic method to measure it otherwise besides putting it into an oscillator and calculating it that way.
trailkeeper (November 30, 1999 at 12:00 am)
Since your on this subject. If someone has a capacitor and wants to know the exact value of it, you can do it with a sinewave function generator. I'm not sure of the specific formual I used since (maby Fhz vs. Cx), but it was a simple one of the reasctance of a capacitor: Cx. I used a capacitor and a known resistor in series, maby 100ohms exact, and at 1000hz, then measured the voltage drops, etc and put it into the formual, and it worked. It will also work for inductors.
radioam232 (November 30, 1999 at 12:00 am)
Indeed a very good way of constructing. Many modern multimeters can measure capacitance, though I dont know if they reach 1 - 100 PF.
radioam232 (November 30, 1999 at 12:00 am)
Thank you. The capacitance tester I have built with a squarewave oscillator. Though I cant remember very well all the ins and outs.
radioam232 (November 30, 1999 at 12:00 am)
Yes it is. The Voltage depends on the dieelectric material(quality) and the space in-between the plates. I did not test the temp. factor, but I presume it is OK with high quality dieelectric materials.
edudrepus (November 30, 1999 at 12:00 am)
I can't get enough of that voice.
coolbluelights (November 30, 1999 at 12:00 am)
I tried to make some rolled capacitors with aluminum foil and plastic film, but I never really had a way to measure the capacitance
AllAmericanFiveRadio (November 30, 1999 at 12:00 am)
Neat and very useful, piratical also. I really like all the home brew equipment you have made. |
