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Author Topic: Dally, Shark & Ruslan workbench  (Read 55589 times)

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Yes, that is the same pulse-burst generating circuit that was featured in the video by Stalker at the time index 6:24.
https://youtu.be/Bhc1xFNgrVA?t=384

I think it is important to remind everyone that this is not the method of generating pulse-bursts in your present replication.

Correct,  presently i am working with the transistor driven "Kacher control board" to generate a burst of HV pulses on the antenna.


Itsu
   

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What is the most major difference between them (in one sentence) ?
Is it external vs. internal excitation ?

Kacher is self oscillating, Tesla coil feed by pulse bursts generated by control board.
There is opinion that it is easier get device working with kacher
because it has property "automatically" resonate on coil's frequency

Vasik


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Correct,  presently i am working with the transistor driven "Kacher control board" to generate a burst of HV pulses on the antenna.


Itsu
So ever heard of automatic frequency control ?
Also TK talks about he found a way of locking the two frequencies in frequency and in phase in his garden video (section in his flat), with out it neither one nor the other will run for long with out drift.

Regards Sil
   

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So ever heard of automatic frequency control ?
He has and even has built one based on the 74HC4046 PLL. See here.
However, it is much more complex than the self-oscillating Kacher with one BJT in its feedback loop.
   
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He has and even has built one based on the 74HC4046 PLL. See here.
However, it is much more complex than the self-oscillating Kacher with one BJT in its feedback loop.

Verpies,

In the PLL schematic, where was L1 located?

What did OUT1 and OUT2 drive?

Very unorthodox use of the 4046... 

PW
   
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"niz resanans" means "lower resonance"
"verh resanans" means "higher resonance"

Please note that Alexeev schematic functionally close to Stalker's schematic, just different components used
However Alexeev used different tuning (frequencies etc)
So don't be confused with differences.

Vasik

Vasik,

Thanks for the translation.

PW
   

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NickZ,

Aren't we supposed to assume that someone already made this work a "first time"?

Do you have a photo of your replication you could post, or a link to one, that I could take a look at?

Thanks,

PW


   PW:  Since you asked...
   Here's a couple of images of my set up. The one showing the three 200w bulbs was powered by a 18v, 6 amp laptop wall adapter. And no the bulbs are not fully lit. I have not seen anyone of us that has shown a higher output, using any of those fancy drivers circuits.
However, that is not the point. The point is will it self run... And the answer is, not yet.
   It's the same device that is still on my bench, after all these years. Digital deco art... it will almost self run, but, it still needs a little push.
   
   NickZ
   
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   PW:  Since you asked...
   Here's a couple of images of my set up. The one showing the three 200w bulbs was powered by a 18v, 6 amp laptop wall adapter. And no the bulbs are not fully lit. I have not seen anyone of us that has shown a higher output, using any of those fancy drivers circuits.
However, that is not the point. The point is will it self run... And the answer is, not yet.
   It's the same device that is still on my bench, after all these years. Digital deco art... it will almost self run, but, it still needs a little push.
   
   NickZ

NickZ,

Thanks for posting your photos.  I remember seeing them now some pages back (the sag gives it away as yours!).

I'd be tempting to rotate the coil assembly 180 degrees, fire it up till warm again until it sags back down to a pre-positioned support at the TC/grenade position (or use hot air).

PW

   
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Itsu,

Does your version of this replication have one side of the "inductor" driving the grenade grounded or is it floating from ground?

("inductor" meaning the coil surrounding the small end of the grenade and driven from the yoke output, ie, the grenade "primary")

PW
   

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PW,

its floating like shown in the red circle in this modules connection diagram.

Itsu
   

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In the PLL schematic, where was L1 located?
I don't remember but there were videos made of this circuit in operation.
It was not applied to the Stalker type of device.

What did OUT1 and OUT2 drive?
I was getting it ready to drive a powerful push-pull circuit, since that is what TL494 excels at.
In the schematic, only OUT2 was used to drive and follow the resonant frequency of the series L1C1 circuit as a POC.

Very unorthodox use of the 4046... 
Only the U3 was doing something original (i.e. converting the 74HC4046 clock to the TL494 clock).
   

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I changed my 4 turn primary kacher coil to a new 6 turn one.

But there is hardly any change in collector signal nor kacher output signal.

We still have the "reflections" with increased amplitude, see screenshot 1  with yellow the collector signal, and red the nearby to the kacher secondary top probe.



When disconnecting the ferrite transformer and antenna from the kacher secondary top, the signals get way lower (frequency higher), but still these "reflections" with increased amplitude are seen, see screenshot 2 (same settings as screenshot 1).

Itsu


   

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We still have the "reflections" with increased amplitude, see screenshot 1  with yellow the collector signal, and red the nearby to the kacher secondary top probe.
Yup, there is an apparent disparity between the voltage at the collector and the electric field near the Kacher's secondary hot end.
   
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PW,

its floating like shown in the red circle in this modules connection diagram.

Itsu

Itsu,

I would like to impose upon you to make a few scope measurements.  You will have to be able to make differential measurements with your scope.  Please let me know if your are willing to do so.

For now, these measurements only need be a single diff channel with an external trigger.  Initially, you can try using the two channels of your lower cost Owon scope to make these measurements.

Are you familiar with using a two channel scope to make a single channel differential measurement (ie, invert and add one channel to the other)?

Here is a brief tutorial:

Use a matched pair of 10X probes.  Remove the ground leads from the probes.  Connect the probe BNC's to the scope's two channel inputs.

Connect a wire (14-16 gauge) between the scope's ground lug and the ground (lug?) on a function generator.  Connect a second ground wire between the scope's ground lug and the push-pull PCB ground.

Connect a third X1 probe (no match necessary) to the external trigger input and the tip of the probe to the scope's calibrator post.  Set scope to trigger on the external input.   

Connect both of the 10X probe tips to the scope's calibrator terminal.  Set both scope inputs to AC coupling and display the cal signal on both channels of the scope.  Set vertical gain for around 50-60% of the display height for both channels' displayed square wave.  Overlap the square waves and center them about the zero volt base line (center the two square waves vertically on the display).  Set the horizontal so as to display one or two cycles of the cal signal.  Keep both vertical gain settings identical.  You should see two overlapping square waves. 

Set the compensation on the probes for best HF response (minimum undershoot/overshoot on leading edge of cal square wave).   

Set the scope so as to invert one channel and add it to the other channel (scope used must have this capability, most do).  You should now see very little signal.  Increase the vertical gain on both channels two or three ranges.  You should still be seeing very little signal (keep the vertical gain identical on both channels).

The residual signal that you will probably see at this point could be: very close to nothing, a small amplitude but nicely flat square wave, or a leading edge/HF peak with or without a visible bit of square wave.

If you see a hint of HF peaking, adjust ONE probe's compensation to minimize that peak and flatten any residual square wave.


Depending on the scope used (some may or may not be able to do this):

To eliminate any residual square wave, take one channel's vertical gain out of cal and adjust gain to minimize the display of residual signal.  Depending on the scope, if a minimum cannot be reached using one channel's vertical gain, put that channel back in its cal position and try minimizing the residual with the other channel's vertical gain.

Some scopes cant do this with the required resolution, depends on scope design.  If not, you will need to live with the residual. 

Now:

Disconnect one probe from the calibrator post and touch it to the ground lug on the scope.  You should now see the the calibrator square wave and be making a differential measurement.  Increase or reduce vertical gain as needed, by reducing the vertical gain on both scope channels.  The vertical gains on both channels must be set identically at all times.

You are now measuring the scope calibrator differentially.

Set your function generator to output a 10VPP, 100K sine wave.  Connect the FG's sync output to the scope's external trigger input.  Trigger the scope on this external input.

Connect one probe tip to FG ground and the other probe to the FG output.  The scope should display the FG's sine output.  Adjust the vertical gain on both channels to display the FG output at a reasonable height on the scope display (again, keep both scope channels' vertical gains identical at all times).   You should be seeing the FG output on the scope display.  There should be no clipping of the sine waveform. 

Set FG for a 10VPP 100K square wave.

Adjust the time base and both vertical gains to display a cycle or two of the square wave (keep both channels' vertical gains identical at all times). 

Now connect both probe tips to the FG output.  You should see very little signal.  If you see any residual HF peaking on the display, you can adjust ONE probe's compensation to minimize that peaking.

Post a shot of the scope making a diff measurement of the FG output (one probe to FG out, other probe to FG gnd) and another with both probes on the FG output.  This demonstrates the diff measurement and the common mode rejection.

Let me know if you have any problems doing this, but if all has gone well, you can now make AC coupled differential measurements with decent enough common mode rejection for the required purpose.

Once you are able to do this, we can discuss the measurements I would like you to make if you are willing to do so.

Thanks,

PW
   

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What about probe deskewing ?
I think Itsu's scope has ±10ns deskewing range.
   
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What about probe deskewing ?
I think Itsu's scope has ±10ns deskewing range.

Verpies,

Itsu's low cost Owon has deskewing?  Amazing...

I only require a few meg of measurement bandwidth and don't need much amplitude accuracy.

I am only concerned with having a fair amount of CMR and not clipping the input with CM signals.

Measurements will be made only at the circuits lowest operational voltages.

PW



   

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I changed my 4 turn primary kacher coil to a new 6 turn one.
But there is hardly any change in collector signal nor kacher output signal.
We still have the "reflections" with increased amplitude, see screenshot 1  with yellow the collector signal, and red the nearby to the kacher secondary top probe.

Itsu,

try something like this

Vasik


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The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

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PW,

No problem doing these measurements, and thanks for the differential probing setup / tutorial, thats quite an elaborate scheme to follow.

Let me set it up later today to see if the OWON scope is able to do so, else i will use the TDS 3054B.

No probe deskewing on the OWON as far as i know / can see, the ±10ns deskewing range is for the TDS 3054B.



Vasik,

you mean to use such varaible capacitor across the primary of the kacher to find the sweet point without these "reflections" with increased amplitude?

I have 2 of those, but with way more space between the plates and thus much less capacitance, like 25pF to 350pF each, maybe i can use those.


Itsu
   

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Vasik,
you mean to use such varaible capacitor across the primary of the kacher to find the sweet point without these "reflections" with increased amplitude?
I have 2 of those, but with way more space between the plates and thus much less capacitance, like 25pF to 350pF each, maybe i can use those.

Itsu,

Yes, variable capacitor across the primary of the kacher.
You can find these capacitors e.g. in old tube radios.
One on the picture has 3 sections 15-450pf, connecting them all in parallel make nice range for tuning.
Alternatively you can connect some small caps in parallel.

Vasik


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The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

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Itsu,

Yes, variable capacitor across the primary of the kacher.
You can find these capacitors e.g. in old tube radios.
One on the picture has 3 sections 15-450pf, connecting them all in parallel make nice range for tuning.
Alternatively you can connect some small caps in parallel.

Vasik
So your talking about adding capacitors across the high voltage winding if so they are going to have to have a 3- 6kv rating.

The other thing is isn't there some thing missing like how does one self generate the 'VORTEX', big question inother words in Verpies
standing wave diagram how are the FIXED NODES set up in eather the Tesla coil or Katcher or is it done in the Grenade or do we simply
drive some NAILS into one or the other coils ?  ;)
   

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So your talking about adding capacitors across the high voltage winding if so they are going to have to have a 3- 6kv rating.
The scopeshots indicate that there is only 150V on the primary of the Kacher.
   

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So your talking about adding capacitors across the high voltage winding if so they are going to have to have a 3- 6kv rating.

No, I am talking about adding capacitor across kacher's primary coil

Vasik


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The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   

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No, I am talking about adding capacitor across kacher's primary coil

Vasik
Yes it's weird, the primary is wound on as a secondary  ;D

Any way I tried that and it is weird as i can try various values and it peaks at 2.6 mhz is a peak with a 1nf, that way everything above 2.6 mhz is cut off
but I cant get it any lower like 1.98 would be better because if i add any other small values it starts eating into the 2.6mh and eroding it q factor and moves
the cut off frequency lower down,  Work that one out !
   
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PW,

No problem doing these measurements, and thanks for the differential probing setup / tutorial, thats quite an elaborate scheme to follow.

Let me set it up later today to see if the OWON scope is able to do so, else i will use the TDS 3054B.

No probe deskewing on the OWON as far as i know / can see, the ±10ns deskewing range is for the TDS 3054B.


Itsu,

The setup only sounds elaborate.  Once you've done it a few times, it takes no time at all.

Tweaking one channel's vertical gain for minimal residual square wave adjusts LF common mode rejection, and using one probe's comp to get rid of any HF peaks adjusts HF common mode rejection.

Keep in mind all scopes around here are still analog, so we'll see how well it works with a DSO.

I am mainly interested in seeing the waveform across the inductor (grenade primary...) without the TC operating, just the PP.

You can also lower the PP driver voltage for the measurement.


PW 

   

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PW,


the problem i encounter with the OWON scope is at this (early) step:

Quote
Set the scope so as to invert one channel and add it to the other channel (scope used must have this capability, most do).  You should now see very little signal. 
Increase the vertical gain on both channels two or three ranges.  You should still be seeing very little signal (keep the vertical gain identical on both channels).

As the screenshot 1 shows, the green math trace when set at CH1+CH2 shows an added signal, not your  "very little signal".

When i set the math function to CH2-CH1 (or vv), then the green math trace shows your "very little signal"!

Doing the same on my TDS 3054B scope does show the required "very little signal" when both channels are ADDED, see screenshot 3

So i better use the TDS 3054B scope for this measurement the more as i won't be using the kacher.

Itsu
   
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