ENERGY AMPLIFICATION

[TinselKoala]

@forest: The suspense is killing me! Would you _please_ tell us the part number of the diode you were using that gave you the 4 amp current draw? And also if you tell us the type/brand of your analog oscilloscope we may be able to help you get the information you need from it.

Here is my levitator system, that uses the _exact same_ circuit on the coil-driver side, controlled by a microprocessor (arduino) that is sensing position by a photoresistor (or phototransistor) detecting a shadow edge and driving the coil in response. The performance of the circuit was much improved (greater stable levitation distance, much less audible noise, much cooler mosfet) by the addition of the ultrafast high-current diode as shown in MarkE's diagram.

http://www.youtube.com/watch?v=xkiGTWODERo



@Zd: making proper measurements, being able to communicate and share those measurements, and discussing the use of well-known techniques to improve performance of commonly used systems,  is NOT off-topic. Sorry that it isn't simple enough for you, but there it is.

[forest]

Tinsel

Diode was FES16JT . Later I used HFA08PB60.Little more better. I created a snubber with 10uf/400V cap and this diode , with additional neon and transil diode in case of too much voltage ;-). I ended up with just 72V of collected energy from kickback. It need just a little improvement. Thanks to MarkE, we now know the important factor - impulse time must be shorter then L/R constant if  you work with this kind of circuit (or flyback,push-pull etc). trust me, it was valuable tip ! I still have to find why it is important. I knew those time constants are CRUCIAL in every resonant overunity devices. :-)
My scope is old polish brand Kabid DT-525a. What I need to know is how to set trigger so both channel would be synchronized in time, so I could see both signals (not just a A-B mode) and find if there is a correlation between one signal going down and other up or something like that...

I'm now in other town til the end of the week 

P.S. Besides, I feel that my talk is useless, seems there are silent watchers there who knew exactly where this is going to...but time is progressing fast and something need to be changed before we destroy environment and rise global temperature 4C above current level...

[MarkE]

Your diodes are plenty fast.  The issue is that you are pumping up the inductor.  What is your intention?  Where do you want to deliver power?

If you want to see both channels relative to one channel, let's assume ch. 1, then trigger on ch. 1 only.  If you sweep in chopped mode you will see both waveforms but will be frequency limited by the chopping rate.  If you use alternate sweep, then you will see one channel on one triggered event and the other channel on the next.  This should not be a problem for this type of circuit.  The last tip I can offer is make sure that you are using the Normal trigger mode.  Do not use the auto trigger mode.

[TinselKoala]

Yes, I agree, those diodes are great, better than any I have in my junkboxes. The issue then is the duty cycle of the signal, as MarkE illustrates. If you are trying to capture the inductive collapse spike produced when the coil current is shut off by the mosfet, into a capacitor instead of recirculating it,  then you should use a shorter duty cycle, and this should be easy to arrange with a little change in your programming of the controller.

ETA: and of course if you are using a parallel-connected neon to limit the cap voltage... the voltage will be limited to the neon's turnoff threshold which, for NE-2 is going to be just about what you reported!

[TinselKoala]

I think your scope has an external trigger input. This is what you should be using if you want good time synchronization between the A and B channels, and use "ALT" mode for the "System Y". Use the gate signal from the microprocessor, (or another output of the MCU that is synchronized with the signal fed to the mosfet gate) fed to the external trigger input of the scope. Top right BNC jack in the photo, if I am understanding the layout correctly. I also found the Service Manual but it's in Polish of course and I can't read it.

http://elektrotanya.com/kabid_dt-525a_oscilloscope_sm.zip/download.html