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Re: cap tester
Tesla List wrote:
>
> > I need a capacitor tester to check the value of my 2 Tesla Coil rolled oil
> > filled capacitors. The value should be about .008 uf.
> >
> > The only thing I own is a digital volt meter and a soldering gun. My meter
> > does not check capacitors. I don't want to spend $200.00 for a new meter
> > that checks caps.
> >
> > Does anyone know anyplace that sells low cost capacitor meters? Does anyone
> >
> > know where to buy a KIT for a capacitor tester? Does anyone have a circuit
> > for a capacitor tester that can be built from parts?
>
> A recent issue of Radio Electronics (I think) had a circuit that you could
> build to turn your DVM into a capacitance tester. If you need more info,
> I could check the particular issue for you at the library.
>
> Steve Roys.
Do you have a DMM? Of any way of measuring AC Amperes? If you do, you
can measure capacitance. This is from an old text book and I have tested
it against known values with sucess. It follows:
Find the Capacitive reactance: Xc=V/I V=volts I=Amps Xc=Ohms
Now C=159,000/(F x Xc) F=frequency in hertz (of the mains 50 or 60 hZ)
C=capacitance in uFd
The following test setup is suggested: Place the Cap in parallel with
the 110/120 V AC mains. Measure the AC volts across the Cap. Now
connect your ampmeter
in series with one of the lines to the Cap. Apply power and read the
measured current.
David Trimmell