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Author Topic: Dally, Shark & Ruslan workbench  (Read 76281 times)

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Itsu,

Please make first kacher work in continuous mode.
Once it working, enable gating.

It is not stating now, probably you need to switch primary coil ends.
If that does not help, check power supply wires.

I think I already explained this but it seems not coming thru.

Vasik


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Anyone who has ever designed an oscillator knows that some measures must be taken to ensure oscillation startup.
...and to maintain oscillations the phase shift of the feedback must be appropriate and the feedback'a gain must be high enough, too.
   

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...and to maintain oscillations the phase shift of the feedback must be appropriate and the feedback'a gain must be high enough, too.

Use an opamp/ comparator and you have both

Regards

Mike 8)


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As a general rule, the most successful person in life is the person that has the best information.
   

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In the post you referenced, all appears to me to be as expected.  Q6 begins to turn on as Vbe is approached and turns on fully as Vbe is reached and the set current flows through the Q6 base-emitter.

Anyone who has ever designed an oscillator knows that some measures must be taken to ensure oscillation startup.  Q6 is turning on very slowly.  Possibly too slowly to stimulate oscillation start up (without some external stimulus).

Even in your posted scope shots with R17=3.3K, it appears we are only seeing LC ringdown at Q6 turn off (unless increasing TC width allows Q6 to be on long enough to start oscillating).

Try tacking the 3.3K resistor across the 8.2K on the board.  This will increase base current to around 6ma and collector current to 500ma, but at the short on times, dissipation should not be a problem.  It will let us compare what speeding up Q6 a bit more does to the waveforms.

It may be necessary to continue decreasing R17 (speeding up Q6 turn on) until oscillations start on their own.  If that value of R17 is too low (i.e., more base/collector current than desired), R18 can be decreased to shunt additional current away from the base.

I've been studying the schematic with HO and LO connected both ways, and it probably makes more sense the way they are currently connected. 

PW

PW,

ok,  thanks for the info.

Not sure what you mean by: "Try tacking the 3.3K resistor across the 8.2K on the board".

I am building another kacher setup with variable R17 and R18 and the posibility to measure the base current.
Hopefully it will give some more details on the working of this part of the circuit.


Good to know that HO and LO are making more sense the way they are currently connected.


I have no problems with starting the oscillations, not sure where that comes from.

Itsu   
   

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Itsu,

Please make first kacher work in continuous mode.
Once it working, enable gating.

It is not stating now, probably you need to switch primary coil ends.
If that does not help, check power supply wires.

I think I already explained this but it seems not coming thru.

Vasik

Vasik,

i have no problems with starting the oscillations, not sure where that comes from.

The oscillations i see lack some power right now and changing primary coil ends (which i do regulary) makes some difference, but not much.

Itsu
   

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Vasik,

i have no problems with starting the oscillations, not sure where that comes from.

The oscillations i see lack some power right now and changing primary coil ends (which i do regulary) makes some difference, but not much.

Itsu
Itsu what i noticed was the oscillations dont span rail to rail and it makes the JT get very hot it realy needs some kind of driver to do that
but then it's interfacing it ! fun ain it ;D
   

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Use an opamp/ comparator and you have both.
Unfortunately Stalker's Kacher circuit does not utilize any op-amps.
We have to tune the phase and gain of the feedback signal by other means :(
« Last Edit: 2021-06-19, 23:55:19 by verpies »
   

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Yes if the driver is a solid signal held to either one rail of the other then it can not be influenced
The BJT's base driver which I posted here, does not hold the base stiffly to either supply rail, because the resistors R17 & R18 allow the base to "float" a little.  Thus, the base can be influenced by the signal coming from the antenna/coil.
Additionally, R17 cannot pull the antenna/coil's signal down to the VCC rail because the diode D1 prevents it.

...by deliberate self oscillation one would need to gate it digitally.
Please explain what you mean by "deliberate" self-oscillation.  I thought that self-oscillation is usually spontaneous.
Anyway, because the base is not held rigidly in this circuit and can be influenced by the signal arriving from the feedback (antenna/coil), that creates conditions for self-oscillation when the phase of the feedback signal and the gain of the BJT are appropriate.

This later circuit does the job a bit better. Also the rise and fall transitions appear to be important.
By "the latter circuit" do you mean the circuit you've attached in this message ?
If "yes", where is the feedback path which influences the signal on the gate of that last power MOSFET (K2611) ?
   
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"Try tacking the 3.3K resistor across the 8.2K on the board".

I meant to "solder", the leads of a 3.3K resistor across those of the 8.2K to temporarily speed up Q6 on time (and Ic).  It would be easier/quicker than removing the 8.2K.

Quote

I have no problems with starting the oscillations, not sure where that comes from.

Itsu

Are you sure?   In your response to Vasik, reply #989, at the red arrow you drew on the scope shot, Q6 is turning on, but oscillations do not start to occur until the Q6 turn off point.

In the scope shot of reply #377 (with R17=3.3K) the same seems to be occurring, that is, oscillations begin just as Q6 is turned off.   

If adjusting RV7 for a wider pulse width does not allow Q6 to begin oscillating while it is turned on, it is likely the oscillations you are seeing are just LC ringdown after Q6 turn off. 

Perhaps, as Vasik suggests, either the collector coil or the antenna coil connections need to be reversed so the antenna is providing positive feedback to the Q6 base.

PW
   

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i have no problems with starting the oscillations, not sure where that comes from.

Itsu,

Yes, you have  :)
Don't you find strange that switching primary ends does nothing ?

Vasik


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Ok,  time out please.........

PW,

1st,  OK about "solder", the leads of a 3.3K resistor across those of the 8.2K.
I got that.

2nd, so you suggest that the low power kacher probe pick up signals i see are just LC ringdown signals, not gated oscillation signals?
Even when adjusting RV7 for a wider pulse width (max), no oscillations seen during the base signal, only after it goes to zero.


Vasik,

when you suggest in your post #1000 here above: "Please make first kacher work in continuous mode" you mean that there should be continuous
oscillations visible with U10 removed, 12V on its pins 10, 12 and 13 and with the kacher secondary bottom lead removed?

If so then OK,  there are no oscillations in that situation, no matter how i connect up the Kacher primary coil.

This happened after i changed R17 from 3.3K to 8.2K, so like PW also suggest could that be the reason?


Itsu
   

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Vasik,

when you suggest in your post #1000 here above: "Please make first kacher work in continuous mode" you mean that there should be continuous
oscillations visible with U10 removed, 12V on its pins 10, 12 and 13 and with the kacher secondary bottom lead removed?

If so then OK,  there are no oscillations in that situation, no matter how i connect up the Kacher primary coil.

This happened after i changed R17 from 3.3K to 8.2K, so like PW also suggest could that be the reason?

Itsu,

We remove kacher secondary bottom lead to set initial Q6 current, to avoid it damage.
There will be no oscillations in this mode.

Continuous mode I mean something like on the picture.
It is good idea set adjustable resistor as R17.
looking on you old photos I don't think it was working properly before.

When you enable gating, oscillations most probably will disappear. You need to bring them back by
increasing TC signal time, increasing power supply voltage and decreasing R17.

Vasik


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Vasik,

Quote
We remove kacher secondary bottom lead to set initial Q6 current, to avoid it damage.
There will be no oscillations in this mode.


Ok, so no oscillations visible with U10 removed, 12V on its pins 10, 12 and 13 and with the kacher secondary bottom lead removed.


Quote
Continuous mode I mean something like on the picture.


Ok, so thats a completly different setup.



Quote
When you enable gating, oscillations most probably will disappear. You need to bring them back by
increasing TC signal time, increasing power supply voltage and decreasing R17.


Ok,  i enabled gating (still R17 = 8.2K) and no oscillations seen (just ringdowns) then increased TC signal time to max., but still no oscillations.

I then gradualy increased the collector PS voltage from 12 to 100V, but still only (stronger) ringdowns, no oscillations even when switching coil leads.

This leaves decreasing R17, so thats what i will do next.


Thanks,  itsu

   
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Vasik,


Ok, so no oscillations visible with U10 removed, 12V on its pins 10, 12 and 13 and with the kacher secondary bottom lead removed.



Ok, so thats a completly different setup.




Ok,  i enabled gating (still R17 = 8.2K) and no oscillations seen (just ringdowns) then increased TC signal time to max., but still no oscillations.

I then gradualy increased the collector PS voltage from 12 to 100V, but still only (stronger) ringdowns, no oscillations even when switching coil leads.

This leaves decreasing R17, so thats what i will do next.


Thanks,  itsu

Itsu,

Even with R17=3.3K, it seems there was only ringdown.

(Edited my question regarding reversing coil connections, I see that you said you tried that.)

PW
   

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Even with R17=3.3K, it seems there was only ringdown.
So the next logical step is to measure the phase difference between the signal at the collector and the signal from the coil/antenna as well as the BJT gain to see if conditions for self-oscillation with feedback are satisfied.

It's either that or blindly trying to adjust the position, distance and loading of the coil/antenna to obtain the proper phase shift and varying the R17/R18 and supply voltage to obtain the proper gain for self-excitation of the Antenna/BJT/Kacher system.
   
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Kacher enabled when Q4 is off and Q5 is on.

Vasik

Vasik,

On page 15, reply#361 of this thread, is one of Itsu's scope shots from back when LO and HO were connected as you had originally drawn them on your schematic (LO driving Q4).  This makes the Kacher circuit run most of the time, except for when the TC pulse is high.  Although the oscillations are slow to build, that scope shot does appear to show the circuit oscillating.

Is this closer to what Itsu is supposed to be seeing?

Are you certain that the reversal of the HO and LO connections with HO now driving Q4 (instead of LO) is correct?

PW

   

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picowatt,

Are you certain that the reversal of the HO and LO connections with HO now driving Q4 (instead of LO) is correct?

Yes, I am.
Check original Stalker's schematic and you will also see it.

Vasik


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Itsu,

If decreasing R17 up to 1K does not help, please check
- your inductor (primary) has 6 turns
- your secondary is 37.5 m, I think 18.5 is too short for kacher setup

Vasik


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Itsu,

Yes, you have  :)
Don't you find strange that switching primary ends does nothing ?

Vasik

Vasik,

In this post you attached a scope shot "osc.jpg" showing oscillation and no oscillation.

What signal is the yellow trace?  (TC, HO, LO, etc)

Thanks,
PW
   

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verpies,

Quote
So the next logical step is to measure the phase difference between the signal at the collector and the signal from the coil/antenna as well as the BJT gain to see if conditions for self-oscillation with feedback are satisfied.


i can try that.



Vasik,

Quote
If decreasing R17 up to 1K does not help, please check
- your inductor (primary) has 6 turns
- your secondary is 37.5 m, I think 18.5 is too short for kacher setup

Kacher primary has 4 turns and secondary is about 37m long.



All,


Please take a look at post #823 here: https://www.overunityresearch.com/index.php?topic=3926.msg92607#msg92607

There i just had the problem of blowing up my PS (due to too much HF/RF i guess).

It still had the 3.3K R17 resistor in and i had 1.5KV of oscillations measured directly with the HV probe.


After that i got the IR2110 pin 1 not working problem and i changed R17 to 8.2K and i never had any oscillations back that i know of.


So i know that with R17 = 3.3K and 12V on the collector using my 4 turn primary and 37m long secondary kacher coils it oscillates.


I will revert back to that setup to see if i can repeat it.



Itsu
   

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PW,

In this post you attached a scope shot "osc.jpg" showing oscillation and no oscillation.
What signal is the yellow trace?  (TC, HO, LO, etc)

It is HO pin 7 IR2110, going to Q4 gate.

Vasik


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What signal is the yellow trace?  (TC, HO, LO, etc)
It is HO pin 7 IR2110, going to Q4 gate.
So it looks like the pin 7 signal is high for a longer time than low.
...and pin 1 signal is high for a shorter time than low.

Both of Itsu's and Vasik's scopeshots show that timing of pin 7:



green:  kacher output (probe near top kacher coil)
purple: base signal Transistor
yellow: pin 7 IR2113
blue:   pin 1 IR2113
   

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Itsu,

Yes, you have  :)
Don't you find strange that switching primary ends does nothing ?

Vasik
It simply means there is not enough pick up signal for feed back.

So how do you explain the Adrian Video's where he has a Tesla a 1/4 wave or 19m wind, I tried it and it don't work.
Rxplain that one  ;D  'if you can'.
   
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PW,

It is HO pin 7 IR2110, going to Q4 gate.

Vasik

Thanks for the reply Vasik...

Is the blue trace in the same scope shot a probe laying next to the Kacher or the Q6 collector?

How warm does Q6 get during operation?

PW
   

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AG,

Ok.
You posted scope traces of IR2110 outputs.
I think they are inverted.
To say for sure I need see TL494 output on same screen.
Kacher enabled when Q4 is off and Q5 is on.

Vasik
Yes i have just been looking at Verpies scope shot he has posted and I think your right!
many thanks for your ionput it's taken a lot to find out what fact and whats not!  O0

Sil
   
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