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 |
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