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Author Topic: Dally, Shark & Ruslan workbench  (Read 52066 times)
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Morbid curiosity:

How many people have this far burnt out one or more gates in their 74HC00?
   

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Morbid curiosity:

How many people have this far burnt out one or more gates in their 74HC00?

Why in particular 74HC00 ?
I think burning one gate is quite rare effect... unless you do some strange things.

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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What is that aluminum foil for ? :
https://youtu.be/tnb8gUifKgk?t=81
   

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The below screenshot shows the Kacher MOSFET gate signal in red and the drain signal in yellow.

Drain diode still bypassed.

There should be more then enough gate signal to activate the MOSFET.

Putting 24V @ 120mA on the drain / primary kacher coil.

Video tour of the whole setup here:  https://youtu.be/2_qfCMo-bFg

Itsu
   

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How many people have this far burnt out one or more gates in their 74HC00?
Not many.

In a properly designed circuit where the input pins are kept from floating (even the unused ones 1,2,4,5,9,10,12,13) and the outputs pins (3,6,8,11) are not negatively or positively spiked by external voltage, which exceeds the IC's supply rails by more than a diode v.drop, and the supply pins (7, 14) are adequately bypassed with 1-100nF ceramic capacitors, then this IC is not overvoltaged and the SCR Latch up is prevented.

The latter can also be caused by ionizing radiation and microwave EMI.
   

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The below screenshot shows the Kacher MOSFET gate signal in red and the drain signal in yellow.
Drain diode still bypassed.
There should be more then enough gate signal to activate the MOSFET.
Putting 24V @ 120mA on the drain / primary kacher coil.
Video tour of the whole setup here:  https://youtu.be/2_qfCMo-bFg

Itsu,

In the video you said "I not sure where the problem is", what problem do you think is there ?
Small output voltage ?

Vasik


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I cannot prove it with the data at hand but it looks too me like Itsu's TC/Kacher's primary to secondary coil geometry (and the grounding bar's position and length) does not support a standing wave well at this frequency.

Why is the primary so wide, anyway ?
   

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Buy me a cigar
A device does not have to use deliberate means of power control because some components  introduce inadvertent regulation intrinsically.

For example, anytime a device utilizes cored inductors, their ferromagnetic saturation limits their energy output.
So in the device being discussed in this thread, the core IS the power regulator you're referring to while also being a transformer, and IMO other things that shall not be named.
Because only Slavs have access to the special cores.
You might be right.


If only we had a time machine!

There were 3, brand new, still boxed Russian colour televisions in the Technical college stores where I learned my basics of TV and Radio repair in the mid seventies. With the advent of " flat screen " technology they're probably long gone. Rubens ??

Cheers Grum.


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Nanny state ? Left at the gate !! :)
   

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Itsu,

In the video you said "I not sure where the problem is", what problem do you think is there ?
Small output voltage ?

Vasik

Hi Vasik,


yes, my feeling is that with 24V there should be much more voltage on the secondary top / antenna.

Presently i can pull a 0.2mm spark with a screwdriver which should be mm's i think, even with this low duty cycle the kacher is running on.

Itsu
   

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I cannot prove it with the data at hand but it looks too me like Itsu's TC/Kacher's primary to secondary coil geometry (and the grounding bar's position and length) does not support a standing wave well at this frequency.

Why is the primary so wide, anyway ?

The kachers secondary to primay coils diameters suppose to be 1:1.6 (PHI?) ratio which it should be the last time i measured it.

Or do you mean the primary windings spacing?

Itsu

   
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   Can some one verify what the max voltage/current should be on Itsu's mosfet gate.
   Itsu has mentioned something about 19v, or so. But, I'm not sure that I understand.
   Seams to me that the gate signal does not need to be that high, but I don't know for sure.
It also seams like he has a glitch somewhere. As the device seams to cut out, and back again, unstable.
   
   Verpies, Itsu is following the same form factor and shape of the Kacher primary coil, as shown by Ruslan/Akula/Stalker, etc...

   Itsu: Can you please post an image of the Kacher signal, at the antenna output. I would like to see the shape of the signal. Thanks.
    Perhaps Utopia Now can also upload an image of his Kacher signals, to compare. Especially the Fet's gate signal.

    NickZ
   
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Hi Nick:
    Was just at the ESTC convention in Idaho, USA and had a talk with Paul Babcock witch peeps say is the man to see about switching. My question was about can you parallel mosfets and not burn them up. He said a resounding yes, I do it all the time. He also added that you can use individual drivers  for each mosfet and drive them with a 1 to 4 ttl gate chip. That meaning it will trigger just fine at ttl levels. You do not have to put 18v on the input to the gate drivers.  On the Fets, you should go with what ever the voltage levels are recommended. Current ones are 18v. Hope this helps you a bit in some way. My fets are being used as a cap dump system and not the Akula thing.
thay
   

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Buy me a beer
I cannot prove it with the data at hand but it looks too me like Itsu's TC/Kacher's primary to secondary coil geometry (and the grounding bar's position and length) does not support a standing wave well at this frequency.

Why is the primary so wide, anyway ?

I agree, I think it is too wide, around a 5mm space would be better, IMO.

On another point, all these circuits are, IMO, to neutralise the ionic charge, ( extract ) from the ambient. With ref: to SM TPU he stated that the electronics had to be within the toroid, in other words shielded from the positive and negative ION exchange and neutrality, neutrality caused by the extraction. Placing a shield over the electronics might make a huge difference in the case of the "TPU", for the Russian type I,m not sure!!! but they are both achieving the same end IMO.

Regards

Mike 8)

PS.  There should be at least 2KV on the Tesla part of this to create the ionic movement.


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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860

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

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   Can some one verify what the max voltage/current should be on Itsu's mosfet gate.
   Itsu has mentioned something about 19v, or so. But, I'm not sure that I understand.
   Seams to me that the gate signal does not need to be that high, but I don't know for sure.
It also seams like he has a glitch somewhere. As the device seams to cut out, and back again.
   
   Verpies, Itsu is following the same form factor and shape of the Kacher primary coil, as shown by Ruslan/Akula/Stalker, etc...

    NickZ

Nick,

according to the IRFP460 datasheet ( https://www.vishay.com/doc?91237 ), the maximum gate-source voltage is 20V, so with my 15V (plus some spikes) i am well within its limit.

ABSOLUTE MAXIMUM RATINGS TC
PARAMETER             SYMBOL LIMIT UNIT
Gate-Source Voltage   VGS    ± 20  V


Also the minimum threshold voltage at which the MOSFET is fully switched on is stated as 2 - 4V which is also complied to with the 15V.

SPECIFICATIONS
PARAMETER                       SYMBOL  TEST CONDITIONS          MIN. TYP. MAX.   UNIT
Gate-Source Threshold Voltage   VGS(th) VDS = VGS, ID = 250 μA   2.0   -   4.0     V


Itsu
   

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Hi Vasik,
yes, my feeling is that with 24V there should be much more voltage on the secondary top / antenna.
Presently i can pull a 0.2mm spark with a screwdriver which should be mm's i think, even with this low duty cycle the kacher is running on.
Itsu

Hi Itsu,

Well, this is Tesla coil, not kacher, you will need tune everything yourself :)
I would suggest you disconnect antenna coil and measure Tesla's secondary coils resonance with signal generator.
Then measure antenna coil capacitance, just for reference.
Then you can try use Gorchilin's calculator to calculate resonance and you will need adjust it to match gradient coil resonance.
Verpies rigth about geometry, center of inductor should be close to first turn of secondary (place where current node will be).

Vasik


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Thanks Vasik,

the present location of the primary is a result for tuning for max output.
Positioning it more to the first turn of the secondary reduces the output (and signal shape) drastically.

But i will look more careful to the kacher / tesla coil setup....

Itsu
   
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Nick,

according to the IRFP460 datasheet ( https://www.vishay.com/doc?91237 ), the maximum gate-source voltage is 20V, so with my 15V (plus some spikes) i am well within its limit.

ABSOLUTE MAXIMUM RATINGS TC
PARAMETER             SYMBOL LIMIT UNIT
Gate-Source Voltage   VGS    ± 20  V


Also the minimum threshold voltage at which the MOSFET is fully switched on is stated as 2 - 4V which is also complied to with the 15V.

SPECIFICATIONS
PARAMETER                       SYMBOL  TEST CONDITIONS          MIN. TYP. MAX.   UNIT
Gate-Source Threshold Voltage   VGS(th) VDS = VGS, ID = 250 μA   2.0   -   4.0     V


Itsu


   Itsu:  Thanks, that is what I needed to know. For now, I'm out of ideas... Perhaps UN can help.

   PS. After watching your video again, I notice that your TC secondary coil is very close to the grenade. Maybe, too close, and affecting the output?
I also noticed that you have much less output before the ferrite rod, compared to at the antenna. Perhaps Vasik is right, and some tuning is needed.
   
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What is that aluminum foil for ? :
https://youtu.be/tnb8gUifKgk?t=81

Verpies,

Looks to be tin plated copper tape with solid wires soldered along the length used for a ground strap throughout his circuit.

Note that this version grounds one end of the grenade secondary, one end of the grenade primary, and the "cold end" of TC secondary to that ground strap.

PW
   

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Hi Itsu,

Well, this is Tesla coil, not kacher, you will need tune everything yourself :)
I would suggest you disconnect antenna coil and measure Tesla's secondary coils resonance with signal generator.
Then measure antenna coil capacitance, just for reference.
Then you can try use Gorchilin's calculator to calculate resonance and you will need adjust it to match gradient coil resonance.
Verpies rigth about geometry, center of inductor should be close to first turn of secondary (place where current node will be).

Vasik


I disconnected the ferrit / antenna from the secondary and carfully measured the secondary resonance frequency to be 2.809MHz.
The antenna coil capacitance compared to ground is 34pF.

so data on secondary:

Secondary coil Fres is 2.809MHz,
Former diameter is 53mm
secondary coil length is 16.6cm
secondary coil number of turns is 216
secondary coil inductance is 685uH (measured)
secondary coil length of wire is 35.9m (calculated)

Using Gorchilin's calculator (http://gorchilin.com/calculator/coil14?lang=en) using this data i get:





With antenna (34pF) as capacitance i suppose to get:






Itsu
   

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Itsu,

I think frequency is too low, you need 1.2Mhz if I remember correctly.
You can change capacitance a little by adjusting distance between turns in  antenna coil, if that is not enough, I guess you will need cut one turn from it.
If you measure resonance with signal generator with antenna coil connected, are measurements match calculations ?
What frequency you feeding to MOSFET ?

Vasik

PS please check input data, do you really have wire 0.77 mm ?


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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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Vasik,

yes, grenade resonance we measured / calculated was at 1.2MHz

When doing the same resonance frequency measurement with ferrite / antenna connected i get 1.018Mhz so slightly low.

Not sure what you mean by "What frequency you feeding to MOSFET", but the pulses fed are at about 1.3MHz, see screenshot (red) here: https://www.overunityresearch.com/index.php?topic=3926.msg93803#msg93803

I have 0.72mm diameter as secondary wire, but its not really tightly wound.

Itsu
   
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Hallo Itsu  I see now where we have different outcomes.
I follow a bit Alexeew`s setup ..  or at least what i think is like his set up of coils.
I have a 19m Tesla that runs at a higher freq of its own .. but with shnyaga and antenna connected it resonates at about 1,76MHz.
I can put a long ferrite rod (1cm x 15 cm) in de Tesla and than go down to 900kHz res freq (Tes, Shny, Ant).
If i want max output at antenna  than i also have to adjust the puls freq. down to 900kHz.

I noticed that when doing so i got less pulses  because 4 pulses  at 1,7MHz need a less amount of on time than 4 pulses at 900kHz. differently stated: at 900kc 4 pulses take more time than 4 p. at 1,7MHz ( so i had to readjust to get exactly 4 pulses again )
Thats also probably the reason why you use more amps at 25 volts (lower freq bigger on time) than i use (higher freq smaller on time) . ( and also because my former measurements were with 4 pulses and you used 5 i think.

I also noticed that my drain signal is getting les clean with the ferrite rod in the Tesla  .. I think than i also heve to adjust the duty cycle from the pulses a bit for optimum performance.

Furthermore i did some measurements with 4 pulses compaired to 5 pulses. at 1,7MHz Mosfet frequency ( even though res freq of Tes. Shny. Ant. was 1,76MHz as I noticed only later. )

Volt      mA   Vtop drain  Antenna   pulses

25V      60     316V        1760Vpp      4
40        91     480          2990           4
70       150    592          5720           4
100     245    784          8kVpp         4
119     300    864          9040           4
 
now with 5 pulses notice the drain voltage is not bigger.

25V     69mA  312V       2120           5
40       125     480         3680           5    0,5mm streamer, spark
70       214     588         6440           5    4   mm  ..  but you have to start by touching and then move away to get 4mm
100     314     768         8800           5
119     370     848         9840           5
   

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He also added that you can use individual drivers  for each mosfet and drive them with a 1 to 4 ttl gate chip. That meaning it will trigger just fine at ttl levels. You do not have to put 18v on the input to the gate drivers.
Indeed, TTL chips run at 5V and that is usually more than the gate voltage (VGS-th) needed to turn on the MOSFET.

However!, merely turning it on is not enough in this application - the speed matters, too.

The +15V which Itsu has elected to use allows his MOSFET to turn on much faster than with +5V.
Also, the current that a dedicated driver is capable of delivering to the MOSFET's gate is much greater than the current which can be sourced out of a TTL gate. A high current source charges the MOSFET's gate capacitance much faster, too.

To discharge the MOSFET's gate capacitance maximally quickly and turn off the MOSFET, up to -20V can be applied to the MOSFET's gate by a high current sink, but applying the maximum allowable voltages to the gate is a bad idea because of overshoots.  So the 15V he has chosen is a good compromise.
   

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Has everyone voted in the poll at the top of this page ?
It is anonymous...
   
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Has everyone voted in the poll at the top of this page ?

No...
   
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