Re: Official air breakdown voltage?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>

When accuracy is important in labs I think it's set up where climate 
is controlled (stp and less than 5% humidity) and the electrode 
diameter is 5-10x the spark length (as close as practical to 2 
infinite planes). Also the DC voltage is raised gradually (forget the 
exact rate, but nowhere near what would be considered impulse). Not 
cheap and easy in MV ranges. I think those conditions are where the 
30kV/cm comes from. As you mentioned, change any of those by even a 
small amount and you'll get lower breakdown voltages for a given 
distance. The 25KV/inch figure varies widely, but a good starting 
point for hobby level stuff where 50-foot+ discharges are seldom 
encountered and high accuracy isn't needed.

Mike
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, November 25, 2005 7:27 PM
Subject: Official air breakdown voltage?


> Original poster: "JT Bowles" <jasotb@xxxxxxxxxxx>
>
>
> I have read all over the net, around 25KV/inch  <<I use this one
> I read on one place,           around 30KV/inch
> Now i have just been told    around 30KV / cm  !!!!   Thats 3 times 
> the voltage I have been told
>
> It is common sense that air pressure, humididty, current, and time 
> of day all affect air breakdown voltage, but:
>
> IS there any official way to determine exactly what air breakdown 
> voltage is? ( such as KV/distance )