Self running coil?

[penno64]

Hi Luc,

It may be that the switching device you are searching for is a solid state relay.

With this, you can totally isolate the two halves of your circuit.

Must admit though, I am like you, not all that strong in electronics.

Good LUCk

Penno

[gyulasun]

...
Is the IRF840 also the same capacitance?  because I get the same effect with it also.
...

Yes, more or less it has similar capacitances in the 1-2V range too, maybe a bit higher than for the IRF640, see Figure 5, Page 4:
http://www.vekoy.com/UserFiles/File/PDF-liitteet/IRF840.pdf

Gyula

[gotoluc]

Hi Luc,

May I ask you what kind of a scope are you using?

It's a 200MHz USB scope, DSO-5200

Comes also with a software spectrum analyzer

You can buy them on eBay.

Luc

[void109]

If you have the time, a circuit diagram would be very useful indeed.  I'm perplexed - in that I think I understand that when you disconnect the battery, you're leaving an open circuit in the drain/source path that's pulsing the core - if that's right (which it may not be), then what in the world would you still need to continue pulsing the gate for?

A circuit diagram would be brilliant     Also - you probably have, or maybe not, but what affect does placing a pickup coil near the magnets have on the effect?  Its all very exciting!  I'd like to go patch up a replication but I'm unsure of the specifics of your circuit.

Thank you for your ingenuitive work, its inspiring.

[gotoluc]

Yes, more or less it has similar capacitances in the 1-2V range too, maybe a bit higher than for the IRF640, see Figure 5, Page 4:
http://www.vekoy.com/UserFiles/File/PDF-liitteet/IRF840.pdf

Gyula

Thanks Gyula

So even if I had an OPTO isolator this would happen also?

Luc