[ARC5] [Milsurplus] If You Need a Regulated Low B+ Supply

[Dennis Monticelli]

True, you can slow switch at 60Hz but if dynamic load regulation matters it
can become an issue.  You would have to rely purely on big oversized caps vs
the feedback loop to hold the voltage steady in the presence of CW or voice
peaks.

Dennis AE6C


On Sun, Feb 14, 2010 at 11:14 AM, J. Forster <jfor at quik.com> wrote:

> One solution to the EMI problem from switchers is to use a low frequency
> square waves, of the order of 60 Hz, rather than 10s of KHz. This enables
> you to use much slower rise/fall switching times and conventional filament
> transformers run backwards. They are bigger and require bigger HV caps,
> but are a lot quieter.
>
> Best,
> -John
>
> ================
>
>
>
>
>
> > While the diagram says "new" this part and the associated circuit dates
> to
> > 1991 when it went into the early GM airbags.  I know because my work
> group
> > designed it.  However, it is still sold along with a plethora of other
> > "Simple Switchers" which have gone through five generations now.  If you
> > go
> > to the National Semiconductor website you will a cluster of easy-to-use
> > design tools that allow virtually anyone to design the switching reg they
> > need right on-line.  All the popular configurations are covered.  You can
> > then order the components along with the PCB from the distributor link or
> > just roll your own by buying the chip from DigiKey.
> >
> > BTW, you can still stack "common-ground" DC/DC converters by feeding them
> > raw DC from independent windings on the transformer.
> >
> > Remember that most switcher circuits are not designed to have low enough
> > EMI
> > to guarantee happiness in our radios.  Pay close attention to short lead
> > dress, good grounding and use shielded inductors vs the cheap solenoid
> > types.  For best results, extra input & output filtering and a metal box
> > may
> > be needed.
> >
> >
> > Dennis AE6C
> >
> > On Sat, Feb 13, 2010 at 11:50 AM, David Stinson <arc5 at ix.netcom.com>
> > wrote:
> >
> >> This cute little circuit is an example of the kind of DC/DC
> >> converter you cannot stack, since in and out have a
> >> common ground:
> >>
> >> http://www.nbglin.com/dc.htm
> >>
> >> Still a neat circuit, though.  I'm gonna get me a
> >> couple to use as "Borg Implants."
> >>
> >> 73 Dave S.
> >>
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