Unable to account for frequency related to Magnet being pulsed by Inductor

[duff]

@Duff
I built and tested the exact same setup you have last year and found the exact same phenomena you describe. It took me a while to find my lab notes on this, about 10 pages, LOL. I produced many variations with multiple coils, multiple magnets etc... .I believe some people here are reading way too much into this, the problem is one of perception, you see a stationary magnet on a stationary coil and have concluded there are oscillations coming from somewhere else. I found the secondary oscillations are from loose coil windings,when the coil windings were varnished the oscillations disappear. I am not saying this effect does not show promise I am just saying I found "where" the oscillations were coming from, it is basically standard induction but the motion is on a very small scale which is misleading. Try "tapping" the magnet on the hard plastic of the wire spool with your scope on the leads and you will see what I mean or hit the table the coil is on. It's pretty cool actually, like a massive microphone or speaker coil.
Regards
AC

AC,

Thanks for the info.

I'm running the osc & driver on DC now and the 959 freq is still there.

I can hold the magnet in my hand above the winding (off the spool) and hear a tone coming from the magnet (domains moving i suppose) and if put my ear to the winding there does seem to be sound there -  it's difficult to tell for sure. 

The coil windings in my case are not loose for it was tightly wound and the wire very stiff (400' #10 magwire) so I doubt the wire is moving but he domains in the wire  in motion.

I did try hitting the coil with the handle of a nut driver and noted no microphonics nor difference in beat tone though it may have been so subtle my hearing couldn't detect it.

Question: When you tried multiple windings did the beat frequency occur above & below the 959Hz in every case??

If the center freq was constant, then I'm wondering why the same frequency is common with windings of different lengths & physical characteristics. I suppose it could be related to the diamagnetic characteristics of copper.


-Duff

[duff]

I have now determined that the beat tone is coming solely from the inductor.

When I previously placed my head outside the coil I heard nothing.
Tonight I placed my head on top of the plastic spool, over the center, with the magnet removed. 
The spool of course has a cylinder center with holes in it ends and sound there is amplified.

What I heard there was two tones and a wavering beat note.
When the magnet is placed on top of the spool it amplifies the affect.


-Duff

[BEP]

When the magnet is placed on top of the spool it amplifies the affect.
-Duff

Amplifies?

Weren't there many folks here that determined a magnet had no real effect upon a coil?

Regardless, Nice work @duff.

[wattsup]

@duff

This is my one and only youtube made way back. May help explain.
http://www.youtube.com/watch?v=XXgL4Wf8zrQ&feature=channel_page

Also, I have pulsed many toroidal transformers with the same sound. Basically a some loose wires being vibrated making like a transducer action or more like a speaker coil.

Added.

When I had the sounds on my toroidal transformer, I took a flexible tube, put one end in my ear and used the other end as a sound prode to identify exactly from which part of the toroid it came from. In my case it was from the wire just at the center air core.

[TinselKoala]

Yes, I am sure the magnet is singing.

It sings sitting on the top of the plastic spool and it also sings if I put it on a piece of paper and raise it above the spool (up to six inches). The beating freq ceases at 959Hz.

I don't have a piezo handy - will check radio shack...

The question is exactly which  ambient fields is it interacting with and how do I prove it.

Here's a pic for better clarity.


-Duff

Edit: It also sings while holding it in my hand close to the top of the inductor though it is very faint.

Uh-huh.