Self running coil?

[gotoluc]

Luc,

Sorry I do not understand where exactly is the 100 Ohm carbon resistor:
in series with the source electrode of the FET?

Gyula

EDIT: Ok now I figured out it is in series with the GND clip coming from the signal gen.

Hi Gyula,

could you calculate an estimated amount of micro watts the switch could be leaking into the circuit using the scope shot I attached below?

I have the pickup coil at 1.85vdc on a 2% 1/2 watt 10K Ohm load = 0.00034 Watts. I'm also only using a half wave rectifier at this time.

The below is what's I scoped across the 5% 100 Ohm MOSFET gate resistor when the coil is adjusted at the neutral point (no current taken or returned).

Please keep in mind that the negative pulses are not used for the MOSFET.

Thanks

Luc

[HarryV]

I have been advised that what you have is a boost converter without a load.

http://en.wikipedia.org/wiki/Boost_converter

what say ye?



Harry

[gotoluc]

Yes i saw it... but i didn't realize it was an update. I thought it only was a 'beautified' version of the first one.   

But it makes no difference. When i connect it like the drawing on reply #110, i also get the sum of the two inductances, not the difference. The direction of my windings is exactly the same as in your picture. The only difference is that i only have 1 layer, you have 5. But this should make no difference.

Tomorrow i will make some tests with the coil.

Hi skywatcher,

are you saying that you get the high inductance when connected as per drawing?

If so, then this is what you want. Also, my tests have shown that there is a preferable side to connect the positive and negative, so this is why we are going into details on the drawing.

Let me know if you are not getting the high inductance value.

Thanks

Luc

[derricka]

Hi Luc,

Your diagram appears to show your Toroid as split. Did you get your Toroid in two pieces, or did you cut it yourself? If so, what kind of saw did you use, and do you know the thickness of the cut or "Kerf"? Thanks for efforts.

P.S. Not sure if you saw my comment about your halogen desk lamp on video 5, but I was hoping you could turn it off, as a test (these lamps can create surprisingly large electromagnetic fields).

[gotoluc]

Hi all,

here is a new video demonstrating a pickup coil and a LED as load.

Link: http://www.youtube.com/watch?v=bgPR9r14zWE

Luc