Re: Recycled Ferrites III (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 20 Dec 2003 13:20:06 -0500
From: RIAA/MPAA's Worst Nightmare <mike.marcum@xxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Recycled Ferrites III (fwd)

Here's some ferrite for those big projects:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3066471384&category=296&rd=1 .
How big does this stuff get? It'd be kewl if I could find a giant rod of it
to put down the center of my 6" secondary and drop the streamers into the
audio range (if I could tune it).

----- Original Message -----
From: "High Voltage list" <hvlist@xxxxxxxxxx>
To: <hvlist@xxxxxxxxxx>
Sent: Saturday, December 20, 2003 10:59 AM
Subject: Re: Recycled Ferrites III (fwd)


> Original poster: Steven Roys <sroys@xxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Sat, 20 Dec 2003 08:58:45 -0700
> From: robert & june heidlebaugh <rheidlebaugh@xxxxxxxxxxxxxx>
> To: High Voltage list <hvlist@xxxxxxxxxx>
> Subject: Re: Recycled Ferrites III
>
> Just a passing comment. Most people just wind an oscilator primary of
20tct
> # 22 wire around a flyback coil  core and 6t ct feed back winding and
power
> the flyback with a free running mv circuit or a push pull oscilator. Most
> flyback coils have pleanty of open space to add wire. While you are
removing
> the flyback coil don't overlook the deflection coil ferrite. It is 2 to 3
> inches in diameter and two piece for easy winding.
>    Robert   H
> --
>
>
> > From: "High Voltage list" <hvlist@xxxxxxxxxx>
> > Date: Fri, 19 Dec 2003 11:07:42 -0700 (MST)
> > To: <hvlist@xxxxxxxxxx>
> > Subject: Recycled Ferrites III (fwd)
> > Resent-From: hvlist@xxxxxxxxxx
> > Resent-Date: Fri, 19 Dec 2003 11:07:45 -0700
> >
> > Original poster: Steven Roys <sroys@xxxxxxxx>
> >
> >
> >
> > ---------- Forwarded message ----------
> > Date: Fri, 19 Dec 2003 21:58:08 +1030
> > From: Matthew Smith <matt@xxxxxxxxxx>
> > To: High Voltage list <hvlist@xxxxxxxxxx>
> > Subject: Recycled Ferrites III
> >
> > Hi All
> >
> > Many thanks to those who have provided such helpful advice on my
attempts at
> > re-using ferrite cored transformers...
> >
> > Going through all the odds and sods that I have lying around, I have
found a
> > load of tiny little transformers removed from the flash boards of
disposable
> > cameras.  These have pretty good turns ratios - may need to watch
insulation
> > if
> > I put more than the usual 1.5V into them.
> >
> > Looking at an alternative way to drive them (if you put more than 1.5V
on the
> > entire flash board, you get smoke after a very short time) with a
suitably low
> > component count.  I have half a rail of LT1171 switching regulators -
this is
> > the 2.5A/100KHz version of the old LT1170.
> >
> > Thinking of hooking an LT1170 onto one of these little transformers
(goodness
> > knows how they will handle 100kHz).  The only topology in the
Application Note
> > which uses two windings is flyback.  However, I don't think that these
> > transformers have a gapped core as a flyback corner should.
> >
> > Can anyone tell me what would the effect be of running a flyback circuit
with
> > no
> > core gap?  If the energy is stored in the gap, would the lack of gap
mean that
> > I
> > wouldn't get anything out of the secondary?
> >
> > My proposed test circuit is VERY basic - LT1171, transformer, rectifier,
> > capacitor.  I can either hook the feedback pin to ground to enable
flyback
> > mode
> > or just leave it floating.  Maybe the latter would be best, since I
would then
> > really just have an oscillator driving the switch.  (The application
note
> > shows
> > this as a legitimate way of doing things - this is how higher voltages
are
> > handled using an external switching element.)
> >
> > Cheers
> >
> > M
> >
> > --
> > Matthew Smith
> > Kadina Business Consultancy
> > South Australia
> > http://www.kbc.net.au
> >
> >
>
>