Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: sparks



At 5:46 AM -0800 2/18/2001, I wrote:

>> > It's about 3 megavolts per meter.

At 05:45 PM 2/18/01 -0800, Larry Woolf wrote:
According to the EB, the field strength for electrical breakdown of air at
atmospheric pressure is 10,000 V/cm. Within thunderclouds, fields of 1000
V/cm are exceeded only over limited areas. This information is also
available in the CRC Handbook in the spark gap section.

Non-experts may be wondering whether there's an inconsistency here.

1) I stand by my assertion that for ordinary household sparks, air breaks
down at about 3 megavolts per meter.

2) 10,000 V/cm equals 1 megavolt per meter.

3) Paschen's law suggests that for larger gaps, the breakdown field will be
smaller:
http://home.earthlink.net/~jimlux/hv/paschen.htm



There is really quite a lot known about this.
http://home.earthlink.net/~jimlux/hv/paschen2.htm
http://home.earthlink.net/~jimlux/hv/hvrefs.htm#Cobine
http://www.eecs.wsu.edu/~pedrow/HV_Engineering/lecture/bdgas/part1/