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Author Topic: The Spike  (Read 28878 times)

MileHigh

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Re: The Spike
« Reply #15 on: December 18, 2015, 03:52:00 PM »
I have a question for you MH, in the spirit of cooperation and good faith.  Also, in line with the topic on this thread. You’ve been bopping about many forums as the self-proclaimed guru of text book. What are the basic factors we should consider when creating the largest spike possible for the least amount of energy? If you had to nail it down to under 10 main concerns, using a coil, what would they be?

No, you didn't really get under my skin.

I would have to say to you that it's a naive question.  The answer is just basic nuts and bolts and it has already been answered in my previous postings in this thread.  Let's ignore resistive losses to keep it simple.  The energy in the spike will be equal to the amount energy you expend to energize the coil, so the "least amount of energy for the largest spike" is a misnomer.  You pick your inductance and your final current before you stop energizing the coil.  The final current is determined by how much voltage you put across the coil and how long you energize it and the size of the inductance.  The resistance of the load or the size of the capacitance determines how high the voltage spike will be or how high a voltage the capacitor will get charged to.  By playing with all of the parameters you can create any kind of spike that you want.

And here's the thing to think about:  Your buddies on EF in your thread would never say what I said above.  It would be wonderful if they all got to that place so they could have a better understanding and do better experiments.

minoly

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Re: The Spike
« Reply #16 on: December 18, 2015, 05:22:03 PM »
The answer is just basic nuts and bolts and it has already been answered in my previous postings in this thread.  Let's ignore resistive losses to keep it simple.  The energy in the spike will be equal to the amount energy you expend to energize the coil, so the "least amount of energy for the largest spike" is a misnomer.  You pick your inductance and your final current before you stop energizing the coil.  The final current is determined by how much voltage you put across the coil and how long you energize it and the size of the inductance.  The resistance of the load or the size of the capacitance determines how high the voltage spike will be or how high a voltage the capacitor will get charged to.  By playing with all of the parameters you can create any kind of spike that you want.

And here's the thing to think about:  Your buddies on EF in your thread would never say what I said above.  It would be wonderful if they all got to that place so they could have a better understanding and do better experiments.



E = -L dI/dt
This was a decent post, thank you for adding in a mostly positive direction. We can see and I hope you agree the other stuff is not necessary and only serves to alienate and antagonize which I’m sure is not your goal.


What is the formula for trying to wind an ideal coil ie… number of turns, Awg, coil inner diameter, height, etc? Or is it easier to work the other way around. What is the formula we can use to plug in these parameters to come up with the spike voltage given the supply voltage and time as you say?


No need to repost if there is already a discussion on this can you point me to it…


MileHigh

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Re: The Spike
« Reply #17 on: December 18, 2015, 10:07:07 PM »
E = -L dI/dt
This was a decent post, thank you for adding in a mostly positive direction. We can see and I hope you agree the other stuff is not necessary and only serves to alienate and antagonize which I’m sure is not your goal.

What is the formula for trying to wind an ideal coil ie… number of turns, Awg, coil inner diameter, height, etc? Or is it easier to work the other way around. What is the formula we can use to plug in these parameters to come up with the spike voltage given the supply voltage and time as you say?

No need to repost if there is already a discussion on this can you point me to it…

There is no such thing as an "ideal coil."  You can look up the formulas for winding coils that will give you the inductance and wire resistance and so on.  For right now the simplest thing to do is start with the basics.

Quote
What is the formula we can use to plug in these parameters to come up with the spike voltage given the supply voltage and time as you say?

Just about any coil you have or want to make can produce the same spike voltage.  You don't even need a formula to determine the spike voltage.  The only thing you need to know is the current flowing through the coil and the load resistance.

You need to start at square one.  I am sure that you have a fist-sized or larger coil where the wire is a fairly heavy gauge so the total resistance is less than 10 ohms.  You can use a coil like that to start.

Compliments of Verpies I attached a diagram that shows a charging current waveform for a coil.  The charging time constant is L/R where L is the inductance of the coil under test and R is the the battery resistance plus the coil resistance plus the transistor ON resistance.  In most cases you can ignore the battery resistance and the transistor ON resistance.  The L/R time constant is called "Tau."   Look at the graph and notice that after one Tau the charging current is 63% of the way to the final current.  That means that you can simply look at the charging (or discharging) current waveform for a coil and work the numbers back and determine the inductance of your coil under test.

In other words:   Coil Inductance = R-effective * Tau.   In the discharging case, R-effective is typically the coil resistance plus the R1 resistance.  Measuring the inductance of a coil with your scope is a no-brainer.  The easiest thing to do is measure the Tau by looking at the voltage discharge curve for the coil across the R1 resistance.  Tau is measured at the point where the peak voltage has decreased by 63%.  You do not need an inductance meter if you keep this simple circuit handy.

When a coil discharges you get a current waveform that is simply an upside-down version of the charging waveform.

I made up a schematic for you for investigating the spike.  You can see how the CVR shows you both the charging current waveform for the coil when the transistor is ON, and the discharging current waveform when the transistor switches OFF.  Notice how at the instant when the transistor switches off the current though the CVR does not change.  You should see an exponential increase in the current followed by an exponential decrease in the current with the two Taus determined by your choices for the resistor values.

TP2 will show you the spike.  When you want to try making very high voltage spikes of several thousand volts, then add optional R2 to make a resistor divider network and use TP3.   You don't have to actually see a 3000-volt spike on your scope display, just see a smaller version of it by looking at TP3.

R3 is an optional resistor for changing the L/R time constant for energizing the coil.  Put in a resistor there then L/R, "Tau," becomes a smaller value.  You can observe this on the CVR.   Likewise optional R3 + R1 plus optional R2 will affect the L/R time constant for the discharging of the coil.

So for starters, how do you get a 100 volt spike to display on your scope?  The answer is very easy.  If you adjust the pulse width so that the CVR is telling you that one amp of current is flowing through the coil, then make R1 100 ohms and you will get a 100-volt spike.  Make R1 200 ohms and you will get a 200-volt spike.  It's that easy.  What if you adjust the pulse width so that the CVR is telling you that two amps of current is flowing through the coil?   Then just make R1 50 ohms and you will get a 100-volt spike.

I strongly urge you to make this circuit and then play with different coils and resistor values until you get to the point where everything makes sense to you and you have mastered it.   Then for the next step you can replace R1 with a large capacitor and start investigating that part of it.  You have be careful through because you could easily over-voltage your capacitors.

If you have any questions please feel free to ask.

I also strongly encourage you to share this schematic and the instructions with your peers on the EF thread because they are also starving for the proper information so they too can understand how the spike works.

MileHigh

TinselKoala

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Re: The Spike
« Reply #18 on: December 18, 2015, 11:31:49 PM »
1.5 V in, over 800 V out.  Circuit is a self triggering JT using principles illustrated by MH's sample circuit:


TinselKoala

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Re: The Spike
« Reply #19 on: December 18, 2015, 11:40:22 PM »
And just for fun....

24 V in, over 200 kV out: ZVS oscillator driving flyback transformer feeding multielement spark gap to make Spikes to drive the primary of a tuned aircore resonator (aka Tesla coil):

http://www.youtube.com/watch?v=aIZClhoU2Xk

Jimboot

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Re: The Spike
« Reply #20 on: December 18, 2015, 11:42:59 PM »
Apparently this belongs here. Merry Christmas to you too MH.
I have no idea what provoked this nonsense.
Luc Jbignes & I just got this message referencing this thread. So I'm copying and pasting here. MH do not send me personal msgs again.
Thanks


"Jimboot, Jbignes5:[/size]Read the following posting that I made:http://overunity.com/16200/the-spike/msg468858/#newNow why don't you two guys tell how much of a fucking horrible person I am?  I must be the devil incarnate, right?You guys listen to me:  I will not be publicly viciously and gratuitously bashed and bashed and bashed by the likes of you.  Sometimes you might not like what I say because when I see bullshit I will say it sometimes.  Tough shit for you.  I do not gratuitously attack people like the way the two of you allege and the way the two of you put in a sustained and relentless attack on me.Do not do it again.Jbignes5, fuck you with your ridiculous MIB fantasies.   Jimboot, fuck you with your passive-agressive psychobabble and your inability to admit when you are wrong.  Both of you need grow up.Luc is being copied because he is not as absolutely awful as the two of you, but because he was a complete jackass when he threatened to kick me of the forum for expressing some frustration like some little petty imaginary wanking dictator.  Shame on you.If you have any issues with me I will listen, but I will not be demeaned and degraded in a hostile and relentless public attack by either of you.I bring real value to this forum as shown by the posting I linked to and all three of you have to know that.Now, the clock has been reset.  I expect the three of you to move on from here with a blank slate.MileHigh"

MileHigh

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Re: The Spike
« Reply #21 on: December 18, 2015, 11:52:43 PM »
You know exactly why I sent you that private email and you are lying.  A few weeks ago you maliciously and relentlessly publicly attacked me over and over and over.  You can't be so daft that you don't remember that so you are lying.

You just made yourself look even worse Jimboot by posting a private email correspondence that told you in no uncertain terms to not do again what you did to me a few weeks ago.

So here you are doing even worse than what you did a few weeks ago.  Posting private email correspondence without my permission is truly awful behaviour.  I showed you a posting in this thread that I made that is a very positive contribution to this forum to illustrate how your behaviour towards me was totally wrong.  How low can you really go?  Shame on you.

Jimboot

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Re: The Spike
« Reply #22 on: December 19, 2015, 12:11:21 AM »
You know exactly why I sent you that private email and you are lying.  A few weeks ago you maliciously and relentlessly publicly attacked me over and over and over.  You can't be so daft that you don't remember that so you are lying.

You just made yourself look even worse Jimboot by posting a private email correspondence that told you in no uncertain terms to not do again what you did to me a few weeks ago.

So here you are doing even worse than what you did a few weeks ago.  Posting private email correspondence without my permission is truly awful behaviour.  I showed you a posting in this thread that I made that is a very positive contribution to this forum to illustrate how your behaviour towards me was totally wrong.  How low can you really go?  Shame on you.
Since you refuse to respect my request of not privately messaging me, I have setup a rule so all your future messages will be automatically deleted. Please stop your harassment.

MileHigh

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Re: The Spike
« Reply #23 on: December 19, 2015, 12:14:31 AM »
Jimboot, you have succeeded in making yourself look badder than bad.

Jimboot

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Re: The Spike
« Reply #24 on: December 19, 2015, 12:20:56 AM »
For anyone else wondering where the ignore settings are.
edit: The reason I posted the MH vile & abusive unprovoked message here, Is that he referenced this thread. I have never sworn or used expletives towards anyone here. I think that is a common courtesy we should extend to one another. Obviously as you can see MH does not agree. I still have no idea why he sent me his vitriolic paranoid ramblings. I think he wanted a gold star or something to show what a well behaved forum poster he is.
« Last Edit: December 19, 2015, 03:12:48 AM by Jimboot »

MileHigh

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Re: The Spike
« Reply #25 on: December 19, 2015, 12:26:07 AM »
The real things to ignore are all of Jimboot's gratuitously malicious and ugly postings and his complete lack of common sense etiquette, Internet or not, and we can get on with this thread.  Sorry that he had to be such a fool as to post private correspondence without my permission.  He has gotten the message so hopefully he will listen.

Edit:

Quote
edit: The reason I posted the MH vile & abusive unprovoked message here, Is that he referenced this thread. I have never sworn or used expletives towards anyone here. I think that is a common courtesy we should extend to one another. Obviously as you can see MH does not agree. I still have no idea why he sent me his vitriolic paranoid ramblings. I think he wanted a gold star or something to show what a well behaved forum poster he is.

Why don't you stop being so full of crap and act like a real man instead of a lying little weasel?  You posted your message to show the world how to go about things in a completely wrong way and make yourself look like a complete idiot, it has nothing at all to do with me referencing this thread.  That's another ridiculous lie.  Wow, what an astute and impressive "Internet Marketing Consultant" you are.
« Last Edit: December 19, 2015, 03:21:20 AM by MileHigh »

MileHigh

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Re: The Spike
« Reply #26 on: December 19, 2015, 12:43:51 AM »
1.5 V in, over 800 V out.  Circuit is a self triggering JT using principles illustrated by MH's sample circuit:

Way to go TK!  I think the fun part to my simple circuit is putting in the voltage divider so that you can measure really high spike voltages without damaging your scope.  If Patrick or his peers build the circuit, they can take some big coils and up the resistance values and see how high they can push it without fear.

For Patrick:  If you were going to start going for higher and higher spike voltages, you will see that the coil discharges in a shorter and shorter amount of time.  So that means that all of the spike energy stored in the coil will be burnt off in the high-value resistance in one shot.  That presents its own problems and I will discuss that.

Suppose that your coil stores five joules of energy with one amp flowing through it and you put a 1/2 watt 10K resistor for R1 and a 1/2 watt 200-ohm resistor for R2.  You are trying to make a 10 kilovolt spike.  Chances are all of that energy being instantly dissipated in the 10K resistor in a fraction of a second will make it explode.   So what you will have to do is simply make a string of 10 1k-ohm 1/2 watt resistors in series.  Then all of the energy in the coil will be instantly dissipated but distributed over all 10 resistors and you will be fine.

MileHigh

MileHigh

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Re: The Spike
« Reply #27 on: December 19, 2015, 03:00:48 AM »
I went too far when I discussed very very high spike voltages.  I also forgot to discuss the practical limits to the maximum spike voltage as it pertains to the transistor and the signal generator.  Depending on the transistor you use, there are specifications for the maximum collector-emitter and collector-base voltages it can sustain when it is switched off.  For the signal generator output, something like a "totem pole" of a series of very fast switching diodes across the output that will conduct starting at perhaps five volts above the nominal high signal generator output would be a suggestion.  This would be to protect the signal generator output if the transistor were to break down from high voltage.  That's where people like TK could give you some solid advice.

Instead of seeing how high you can push your spike voltage, keeping it a reasonable and safe distance away from the break-down voltages of the transistor or MOSFET would be the wise way to go.  After all, the purpose of the investigation is not to see how high you can push the spike voltage, it's to understand how to control and use the spike.

Say for the sake of argument that your transistor can withstand 750 volts when it is switched off.  If you keep the spike voltage to 500 volts and less, you should be fine.  You should not need a totem pole of protection diodes on the signal generator output either.  The real point of the test circuit is to see how a coil generates a spike, and the time it takes for the decay of the spike, for different initial currents through the coil, and for different values of load resistor.  You don't need to see the spike voltages to go into the stratosphere for that.  When you look at the case for an ideal inductor of any inductance value, the theoretical maximum spike voltage is infinity.

If you understand how the spike works and try different coils, try different timings and associated initial currents, and different load resistors, then when you start doing other experiments with pulse motors and related stuff you will understand what you are observing and be in a position to modify and adapt your circuits to your applications.

"Radiant energy" has nothing at all to do with this investigation.  An equivalent mechanical test bed would be a series of flywheels that you spin up to different speeds.  Then you apply disk brakes to the spinning flywheel and measure the force that the spinning flywheel imparts on the disk brakes.  The faster and with more force the disk brakes clamp down on the spinning flywheel the more force will be imparted on the disk brake assembly.  That force is the mechanical equivalent to the voltage spike.

MileHigh

EMJunkie

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Re: The Spike
« Reply #28 on: December 19, 2015, 03:13:28 AM »
I went too far when I discussed very very high spike voltages.  I also forgot to discuss the practical limits to the maximum spike voltage as it pertains to the transistor and the signal generator.  Depending on the transistor you use, there are specifications for the maximum collector-emitter and collector-base voltages it can sustain when it is switched off.  For the signal generator output, something like a "totem pole" of a series of very fast switching diodes across the output that will conduct starting at perhaps five volts above the nominal high signal generator output would be a suggestion.  This would be to protect the signal generator output if the transistor were to break down from high voltage.  That's where people like TK could give you some solid advice.

Instead of seeing how high you can push your spike voltage, keeping it a reasonable and safe distance away from the break-down voltages of the transistor or MOSFET would be the wise way to go.  After all, the purpose of the investigation is not to see how high you can push the spike voltage, it's to understand how to control and use the spike.

Say for the sake of argument that your transistor can withstand 750 volts when it is switched off.  If you keep the spike voltage to 500 volts and less, you should be fine.  You should not need a totem pole of protection diodes on the signal generator output either.  The real point of the test circuit is to see how a coil generates a spike, and the time it takes for the decay of the spike, for different initial currents through the coil, and for different values of load resistor.  You don't need to see the spike voltages to go into the stratosphere for that.  When you look at the case for an ideal inductor of any inductance value, the theoretical maximum spike voltage is infinity.

If you understand how the spike works and try different coils, try different timings and associated initial currents, and different load resistors, then when you start doing other experiments with pulse motors and related stuff you will understand what you are observing and be in a position to modify and adapt your circuits to your applications.

"Radiant energy" has nothing at all to do with this investigation.  An equivalent mechanical test bed would be a series of flywheels that you spin up to different speeds.  Then you apply disk brakes to the spinning flywheel and measure the force that the spinning flywheel imparts on the disk brakes.  The faster and with more force the disk brakes clamp down on the spinning flywheel the more force will be imparted on the disk brake assembly.  That force is the mechanical equivalent to the voltage spike.

MileHigh


MileHigh is right here!

The Inductive Spike is E = -LdI/dt - All this means is that the Magnetic Field, Stored in the Inductor, which is the LdI part, the Negative sign, which is the Polarity reversal, and dt is the Time Rate of Change.

Its simply Induction, it all comes from the Induction Law emf = -NdPhi/dt - Its the same thing!

Radiant Energy/Cold Current, really is a bunch of Horse Malarkey Rubbish! Designed to have people running down Rabbit Holes chasing Magic Rabbits! Its all Induction, it will never ever change.

   Chris Sykes
       hyiq.org

P.S: Yes I used to get sucked into this Radiant Rubbish before I knew better.

MileHigh

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Re: The Spike
« Reply #29 on: December 19, 2015, 03:58:28 AM »
The Inductive Spike is E = -LdI/dt - All this means is that the Magnetic Field, Stored in the Inductor, which is the LdI part, the Negative sign, which is the Polarity reversal, and dt is the Time Rate of Change.

You are close but let me fine tune it.

The voltage generated by a coil of inductance L:  E = LdI/dt

But how do you relate that to what I state in my previous posting?  If the load resistor is zero, then the current through the coil will not change, so then:  E = 0 = LdI/dt where  dI/dt is zero.

The higher the value of the load resistor, the higher the initial voltage and the faster the coil will discharge its stored energy and the faster the current will change:  dI/dt will be a high value for a high value of load resistor.

We can look at the initial conditions to get a handle on what the equation means the instant the coil starts discharging through the load resistor:

We know that the initial voltage is simply the current through the coil times the value of the load resistor: V-initial = (I-initial *R)

So at the instant the coil starts discharging we can say this:  (I-initial *R) = (L * dI/dt)

Therefore the rate of change of the current waveform at the instant discharging starts is: dI/dt = (I-initial *R)/L = V-initial/L

Therefore: L = V-initial/(dI/dt)

That means that by looking at the slope of the current waveform when the coil starts discharging and measuring the initial voltage you can determine the inductance of the coil.