Date:         Fri, 14 Nov 2003 17:20:49 -0500
Reply-To:     David Brodbeck <gull@GULL.US>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Brodbeck <gull@GULL.US>
Subject:      Re: Fwd: RE: "Green" solar battery charger
Comments: To: David Beierl <dbeierl@attglobal.net>
In-Reply-To:  <5.1.0.14.2.20031114170711.073d7f28@pop1.attglobal.net>
Content-Type: TEXT/PLAIN; charset=US-ASCII

On Fri, 14 Nov 2003, David Beierl wrote:

> >of the more compact methods is to put the contacts inside a sealed chamber
> >which is evacuated to a high vaccuum.  No air means nothing to ionize
> >to carry the arc current.
>
> Ah ha!  And you don't get a metal arc?  Are the contacts tungsten or some such?

I'm not sure what they make the contacts out of.  But there's a lot less
vaporized metal available to make an arc than there is air in a normal
breaker. ;)

> But getting back to IC ignition, how much of that is arc?  Does it really
> become the low-resistance point of the system?

It wouldn't surprise me.  I'd expect the resistance of a spark plug arc --
we're talking a fraction of an inch here, remember -- to be on the order
of a few ohms once it's struck.  People who make cool but dangerous
high-energy devices like "quarter shrinkers" sometimes use spark gaps as
high-current, high-voltage switches for this reason.  It's cheaper than an
SCR stack. ;)


David Brodbeck, N8SRE
'82 Diesel Westfalia
'94 Honda Civic Si -- For Sale
'86 Volvo 240DL wagon