John Woodgate wrote in message ...
I read in sci.electronics.design that Jeff Liebermann
wrote (in mppp50ho4dr08ahkb3dlbqkcfkp0ih
) about 'CB Radios, Cellphones and Gasoline Vapor
Ignition', on Sun, 21 Mar 2004:
The gap necessary to create an arc with 22 volts is:
22V / 20,000V/in = 0.001 inches Kinda small, but given a microscope,
a 1 mil spark gap will arc.
But it takes about 350 V to do so. The relationship between voltage and
gap length is very non-linear below about 500 V.
In fact the Paschen curve - breakdown voltage plotted against gap -
has a minimum at around a couple of hundred volts, and the breakdown
voltage starts rising again for very small gaps. The linear right-hand
branch of the graph where you might see a slope of 20,000V per inch
doesn't extend down to 22V.
The theory explaining the conductivity of electricity through gases
was worked out around the turn of the last century, and doesn't seem
to be all that well known any more. Pity.
-------
Bill Sloman, Nijmegen