Power to Depth ratio?

[brucester]

Hi,

I am trying to get my head around pulse current to depth ratio.

I have read on numerous sites that it takes 4 times more power to increase depth by 1 inch?

Is that a realistic statement?

Also, is there a chart or a table or something that shows a magnetic fields distance as amps increase?

Trying to find the optimal pulse width and strength for my detector but very little seems to have been published with regards to this.

If none exists, i guess i will need to buy a dc power supply do the experiment myself :P

I have also read that typical depth is equal to the diameter of the coil.

But what power range is this for?

I mean, if 0.5 amps makes a 10cm coil detect at 10cm, does that mean it will take 2amps for the same coil to detect at 12.5cm?

Is there an equation that describes this relationship?

What is the minimum amount of amps to get a coils diameter range?

If anyone could shed some light on this topic, or provide a link or two it would be greatly appreciated.

Thanks

[Tinkerer]

Hi,

I am trying to get my head around pulse current to depth ratio.

I have read on numerous sites that it takes 4 times more power to increase depth by 1 inch?

Is that a realistic statement?

Also, is there a chart or a table or something that shows a magnetic fields distance as amps increase?

Trying to find the optimal pulse width and strength for my detector but very little seems to have been published with regards to this.

If none exists, i guess i will need to buy a dc power supply do the experiment myself :P

I have also read that typical depth is equal to the diameter of the coil.

But what power range is this for?

I mean, if 0.5 amps makes a 10cm coil detect at 10cm, does that mean it will take 2amps for the same coil to detect at 12.5cm?

Is there an equation that describes this relationship?

What is the minimum amount of amps to get a coils diameter range?

If anyone could shed some light on this topic, or provide a link or two it would be greatly appreciated.

Thanks

This is an interesting subject that we should expand on.

We could say that a certain field strength at a certain depth is good enough for exciting a good amplitude of eddy currents, for a certain target surface area.

If the target surface area is half, we would need to increase the field strength by 2.

For simplicity sake we leave the switch OFF speed out of the equation.


http://hyperphysics.phy-astr.gsu.edu...ic/curloo.html

This calculator is quite useful.

The numbers are for 1 coil loop. If your coil has 20 turns, multiply by 20.

Tinkerer