Re: ferrite mini coil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "rheidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>

To answer your question without a lot of details I will explain it this way.
All magnetic cores can be magnetized to a point where an increase in current
in a coil will not increase the magnetic strength. The core will not hold
any more. This is the saturation point.Like a sponge will hold so much water
and no more.
  Robert  H

> From: "Tesla list" <tesla-at-pupman-dot-com>
> Date: Sun, 20 Jan 2002 18:02:49 -0700
> To: tesla-at-pupman-dot-com
> Subject: Re: ferrite mini coil
> Resent-From: tesla-at-pupman-dot-com
> Resent-Date: Sun, 20 Jan 2002 20:13:47 -0700
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <PeterCGMN-at-aol-dot-com>
> 
> 
> In a message dated 1/20/02 1:27:24 PM, tesla-at-pupman-dot-com writes:
> 
>> Before contemplating any use of a ferrite rod I recommend a
>> flux-density calculation for the expected operating voltage and
>> frequency.  I'd be very much worried about saturation losses and total
>> failure.  About 20 years ago I tried using a ferrite slug to tune the
>> loading coil for a VLF band transmitter, and had serious problems with
>> saturation at 181 kHz with a voltage of only 1000 across the coil, which
>> had about 3 mH inductance. This coil had a cylindrical core about 5/8"
>> diameter.  I suspect that with your transistor radio antenna rod the
>> diameter and area are much smaller, again leading to problems.
>> 
>> Ed
> 
> Okay, once again pardon my stupidity, but what do you mean by the term
> "saturation"
> 
> 73, Kc0Ion, "Ion-Boy"
> 
> 
>