Air impedance

[Wayne]

Hi,

I want to measure the impedance or conductance of air. How can I achieve and what is the possible value of the impedance of the air?
Thank you very much!

Wayne

 

[Sprow]

"Wayne" <ares kwchan@hotmail.com> wrote in message news:<c9rbp8$2m3i$1@justice.itsc.cuhk.edu.hk>...

Hi,

I want to measure the impedance or conductance of air. How can I
achieve and what is the possible value of the impedance of the air?
Thank you very much!

Are you thinking of the characteristic impedance here, or literally
the number of ohms you see on a multimeter?

The characteristic impedance can be found with the permeability of
free space and permitivity of free space and a physics textbook,
should fall out about 377 ohms. I've assumed free space is going to be
close enough to 'air' for you.

If you want the multimeter type then this is clearly dependant on the
moisture content, temperature, ionisation, and distance. Air is a very
poor conductor until it breaks down when it becomes an excellent
conductor: lightning and arc welders for example,
Sprow.

 

[Wayne]

Hi,

I would like to make a device to measure the impedance of the air. I
use a ac current source, (i.e.1kHz) to pass through two electrode in a fix
distance. What is the possible value of the impedance of the air?
Thank you very much!

Wayne

"Sprow" <news@sprow.co.uk> wrote in message
news:2ec0aa9a.0406042355.6eec960d@posting.google.com...

"Wayne" <ares kwchan@hotmail.com> wrote in message
news:<c9rbp8$2m3i$1@justice.itsc.cuhk.edu.hk>...
Hi,

I want to measure the impedance or conductance of air. How can I
achieve and what is the possible value of the impedance of the air?
Thank you very much!

Are you thinking of the characteristic impedance here, or literally
the number of ohms you see on a multimeter?

The characteristic impedance can be found with the permeability of
free space and permitivity of free space and a physics textbook,
should fall out about 377 ohms. I've assumed free space is going to be
close enough to 'air' for you.

If you want the multimeter type then this is clearly dependant on the
moisture content, temperature, ionisation, and distance. Air is a very
poor conductor until it breaks down when it becomes an excellent
conductor: lightning and arc welders for example,
Sprow.

 

[Bob Myers]

"Wayne" <ares_kwchan@hotmail.com> wrote in message
news:ca10rj$10s2$1@justice.itsc.cuhk.edu.hk...

Hi,

I would like to make a device to measure the impedance of the air. I
use a ac current source, (i.e.1kHz) to pass through two electrode in a fix
distance. What is the possible value of the impedance of the air?

You don't want the impedance, you want the breakdown
voltage, if I'm understanding what you're trying to do correctly.
An air gap is an extremely non-linear sort of thing; a very high
impedance UNTIL the electric field exceeds the breakdown
level, and then a very low impedance. What exactly is it you're
trying to do here?

Bob M.