[Prev][Next][Index][Thread]

Re: toroid capacitance (fwd)





=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
 Chip Atkinson 
 http://bhs.broo.k12.wv.us/homepage/chip/info.htm
 --- Everyone is someone else's weirdo. ---
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

---------- Forwarded message ----------
Date: Tue, 12 Nov 1996 12:23:53 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: Chip-at-pupman-dot-com
Subject: Re: toroid capacitance

Hi Chip,
        I'd like to add a bit to my intial reply:

> Hi Chip,
> 
> > How does one measure the capacitance of a toroid?  The only way I can 
> > think of doing so is to measure the inductance of a secondary without the 
> > toroid, and then attach the toroid and measure the frequency of 
> > resonance.  From this, work backwards to get C.  Any other ideas?
> 
> That's it really. You have to measure the capacitance in context.
> 
> Malcolm

ADD:  Measure the coil self-F after measuring L, then add the toroid 
and measure the new F. From the first frequency you can work out the 
resonator C, and from the second, you have resonator C + toroid C.
BTW, you will find that Medhurst's Cself formula will give the 
resonator C to quite a high degree of accuracy.

Thanks,
Malcolm