Kapanadze Cousin - DALLY FREE ENERGY

[Alfeen]

When inductivity does not increase any more although you still increase the current then you have saturation.

Should read:  When inductivity does not decrease any more although you still increase the current then you have reached saturation.

Sorry for the typo. Perhaps you find more of them.   

[itsu]

Hi Alfeen,

impressive read, i will have to reread it severall times to let it sink in.
I was somewhat confused by the notations of the components  (Q5,  C34, D7 etc), but i understand you where talking about the Dally diagram attached below.

I am unable to attach any files presently, so diagram is from verpies his post #274 on page 19.

Thanks,   Regards   Itsu

[verpies]

Should read:  When inductivity does not decrease any more although you still increase the current then you have reached saturation.
Sorry for the typo. Perhaps you find more of them.   

Don't worry about it. There is a "Modify" button above your original message which allows you to edit your post for 12h.

Regarding itsu's schematic: When the mosfet Q5 becomes conducting, a current starts to flow into coil W1.

The schematic that you should be referring to is here.
Itsu's Power MOSFET oscillates at 30MHz even if W1/T1 is removed and 1Ω non-inductive resistor is substituted for it.
His R1 and R2 are both 4.7Ω resistors.

Do those facts change your circuit analysis ?

P.S.
There is no such word as "inductivity" in English language, but I understand what you meant

[verpies]

9 turns of 0.8mm wire wound over a 3mm cylindrical former will pick up every available magnetic noise and is likely to fail as a countermeasure for the 90MHz ringing of itsu. A shielded coil like "COILTRONICS - DR1030-151-R" might probably help for small mosfets with low input capacitance. But it can take only 680mA.

That's a continuous current rating, isn't it?
If yes then theoretically at 0.1% duty cycle it could conduct 680A momentarily, unless it uses a ferrite core.
The shielding of the inductor is a good idea if magnetic interference is present in the place where the coil is located.

When switching the gate on/off a high current is flowing to/from the gate which may saturate the ferrite, change the resonant frequency --> rendering the intended filter effect useless.

For 128nH a ferrite core is not necessary, is it?
...and air cored inductors do not suffer from saturation effects.

Also, the high current (4A-9A) flows to/from the gate only for several nanoseconds, which at 4.6kHz pulse repetition rate (217391ns period) represents less than 0.005% duty cycle, which averages out the current, significantly.

I maybe mistaken, but Diode D7 does not make much sense to me, neither as a DSR nor as a normal diode. It would just consume energy.

When referring to this schematic diagram, the diode D7 plays the role of ordinary Flyback Diode which purpose is to:
1) Prolong the time, during which the core of T1 remains saturated (after Q5 stops conducting).
2) Protect Q5 from W1's flyback voltage spike (after Q5 stops conducting).

Yes, D7 should be a fast Schottky diode with low voltage drop in order to consume the energy stored in T1 as slowly as possible.

[Alfeen]

...and air cored inductors do not suffer from saturation effects.

But they act as a pretty sensitive magnetic loop antenna. Many ham radio guys purposefully construct them for short wave communication. I had three or four of them in use. We could wind a coil on a plastic ring to make it a toroid instead of a hollow cylinder. This combines the advantages of a shielded coil with the saturationless air coil. Toroid coils are widely used for contactless measurement of currents. Magnetic fields outside the toroid cancel each other out. Only currents flowing through the center opening cause induction.

Anyway, my Tesla coil experience gives me hope that in the end we will not need such filter any more. It can be done without ringing and without filters on the gate.

regards