johntee said:
Hi Len,
Sorry I got the wrong end of the stick in your previous reply. I mistakenly thought my topic was becoming too dominant on the forum, ie taking up too much time. As it's alien to my nature to intentionally impose upon people I reactively choose to 'ride into the sunset' with whatever knowledge I've been graciuosly offered. I certainly failed to realise that there are other more appropriate areas, and probably more relevant persons to ask about ferrites and magnetics. With that clarified I feel so much better. Anyhow;
RE: So my question is - do you want a field that has a bias in one direction, or one that alternates from -12000 Gauss to +12000 Gauss?
I'm truly not completely certain at this point, the higher gauss scenario seems very attractive as this follows my original concept of Static magnetic gauss + Circuitry created gauss = mega gauss.
However, your intuition seems to be leaning towards the -12000 to +12000 swinging choice and this leads me to ask whether this lower gauss level I just chose 12000 Gauss as an example is achievable with just the electronic component alone. My limited knowledge of electronics forbids me from knowing the answer to that one. I am likewise asking myself whether I will achieve sufficient depth of penetration in a biological mass with a lower gauss level. These and similar questions have plagued researchers from the year dot so I don't feel alone here. I think the answer is to try one way and if the results are not the desired ones, try the other.
On the latter basis Len, which do you think is the easiest way to create a strong alternating magnetic field in the 12000 gauss area, and could such be made available at different frequencies? I ask this because biological material reacts and responds in sympathy to varied, plus specific frequencies, and strength of magnetic fields.
Quite a bundle of questions, maybe I should be paying you a consultancy fee. ( if only )
Any feedback, postive or otherwise, is very welcomed.
Cheers for now,
John in the UK
John,
Your post of a few days ago stated that the magnet produced 10000 Gauss.
So I chose 12000 Gauss for the flux to be produced by the coil as an example to illustrate what flux would be generated by the combination of magnet + coil, ie. the resultant flux would alternate between -2000 and +22000 Gauss.
Had I chose 30 kGauss, the flux would alternate between -20 kG and +40 kG.
Had I chosen 8 kG, the flux would alternate between +2 kG & +18 kG, ie. it would not reverse direction at any point in the cycle.
I'm just pulling figures out of the air without any real idea of what is practical in order to illustrate my point.
You need someone with more knowledge of magnetics to tell you how much flux a coil can produce.
I don't really have the time to dig out my physics books and revise what I once knew while doing my engineering degree.
So I suggest you start a new thread (with a suitable subject line) and ask for advice on how much flux can be produced from a coil.
But don't make the question too general. I suggest you state (in broad terms) how much flux you want to produce and how it will be directed into the patient.
From memory, the flux depends upon the current, the number of turns and the reluctance of the magnetic circuit.
The answer will also depend upon the frequency range you want to employ.
For high frequencies, you will need a low inductance coil; therefore, you will have to supply a high current to produce the flux.
At lower frequencies, you could use a coil with a higher inductance (ie. more turns) and therefore you will be able to produce the same flux with a lower current.