short pulses for radiant circuits
TRANSCRIPT
qwertyuiopasdfghjklzxcvbnmq
wertyuiopasdfghjklzxcvbnmqw
ertyuiopasdfghjklzxcvbnmqwer
tyuiopasdfghjklzxcvbnmqwerty
uiopasdfghjklzxcvbnmqwertyui
opasdfghjklzxcvbnmqwertyuiop
asdfghjklzxcvbnmqwertyuiopas
dfghjklzxcvbnmqwertyuiopasdf
ghjklzxcvbnmqwertyuiopasdfgh
jklzxcvbnmqwertyuiopasdfghjkl
zxcvbnmqwertyuiopasdfghjklzx
cvbnmqwertyuiopasdfghjklzxcv
bnmqwertyuiopasdfghjklzxcvbn
mqwertyuiopasdfghjklzxcvbnm
qwertyuiopasdfghjklzxcvbnmq
wertyuiopasdfghjklzxcvbnmqw
ertyuiopasdfghjklzxcvbnmrtyui
Short Pulses for Radiant Circuits
[Geben Sie den Untertitel des Dokuments ein]
28.04.2012
0.1 / Draft
Short Pulses for Radiant Circuits 28.04.2012
Page: 1
Table of Contents
1 Overview .......................................................................................................................................... 2
1.1 Disclaimer: ............................................................................................................................... 2
1.2 Policies: .................................................................................................................................... 2
1.3 Abbreviations: ......................................................................................................................... 2
2 Recalling Basics ................................................................................................................................ 3
2.1 Inductances ............................................................................................................................. 3
2.2 Transformers – Common Operation ....................................................................................... 3
2.3 Lenz’s Law and Other Laws ..................................................................................................... 5
2.4 Transformers – Pulse Operation ............................................................................................. 6
2.5 Pulses for Radiant Circuits ....................................................................................................... 7
2.6 Effect of Pulse Width ............................................................................................................... 7
3 Pulse generation .............................................................................................................................. 9
3.1 Pulse transformer in current mode ......................................................................................... 9
3.2 Spark gaps – tesla mode ........................................................................................................ 10
3.3 Pulsing oscillating coils .......................................................................................................... 11
3.4 Pulsing Don Smith circuits ..................................................................................................... 11
3.5 Capacitor Discharge Ignition (CDI)......................................................................................... 11
3.6 Nanosecond Pulses ................................................................................................................ 13
Image Directory
Figure 1 - Flywheel .................................................................................................................................. 3
Figure 2 - Voltage and current (sine wave) ............................................................................................. 4
Figure 3 - Magnetic vortex ...................................................................................................................... 4
Figure 4 - Pulsed transformer .................................................................................................................. 6
Figure 5 - Fourier transformation ............................................................................................................ 7
Figure 6 - Automotive ignition system .................................................................................................... 9
Figure 7 - Tesla's pulse technology (example) ....................................................................................... 10
Short Pulses for Radiant Circuits 28.04.2012
Page: 2
1 Overview Many radiant circuits require short and high voltage pulses in order to trigger radiant events. While
radiant science is still off the trail of the publicly accepted science it cannot abandon dead normal
circuitry in line with normal science in order to succeed.
Many replications show lag of basic knowledge and therefore do not succeed despite extraordinary
enthusiasm.
This workout tries to bring these essential basics to the mind of mere mortals. Math was omitted
wherever possible. It is the expressed goal to support enthusiastic replicators and give them some
tools and thought food being necessary to build successful setups.
This text covers some basic notions regarding inductances and transformers. Transformers own some
properties being overseen by most replicators. Generating short pulses is not difficult but is quite
different from normal operation of ignition coils. Another part of the document covers hints for
adapted circuits and explanations of their function.
This document does not contain schematics ready for copy and paste. Please understand the content
as toolbox and tutorial related to pulse generation.
1.1 Disclaimer:
The content is intended for tutorial purpose only. The setups discussed produce lethal voltages and
you are not encouraged to build or operate them as long you are not an educated person with
knowledge regarding safe operation of lethal voltages.
The text covers notions of the author. Despite widely common request he will not enter any
discussion regarding scientific proof. Facts need to be evaluated and compared with other before.
The scientific proof is the last action only. Nobody is forced to follow these notions
1.2 Policies:
You are encouraged to copy and forward this document at will as long as the content is not modified.
Quotations are allowed unmodified only with added reference (title, version ).
1.3 Abbreviations:
HV = High Voltage
Short Pulses for Radiant Circuits 28.04.2012
Page: 3
2 Recalling Basics
2.1 Inductances
Inductances are well known to resist current changes vehemently.
Imagine a flywheel. The accelerating force conforms to the voltage and the rotation speed to the
current. Conform standard notion the energy is stored in the magnetic field. Apart that other notions
exist proposing that the magnetic field is one effect only while other procedures are involved as well.
Figure 1 - Flywheel
If we try to stop a flywheel we need to deplete the stored energy. Too sudden breaking will unleash
enormous forces because of the inertia of the mass. In electric terms the stop action conforms to
interrupting the current. – enormous voltage will occur because of the “inertia” of the magnetic field.
2.2 Transformers – Common Operation
The common notion is that transformers transform voltages from one level to another level and
along that they feed loads with the requested current. Unfortunately this is not the whole truth and
therefore transformers are widely misunderstood.
This chapter will not cover the whole transformer theory but some important highlights only.
In fact there is no case known where a transformer (ignition coils included) transformed voltages. I
admit that the effects are measurable but these are effects only and not the intrinsic function of a
transformer. Apart that the transforming of voltages measured conforming n1:n2 (winding ratio) is
true for one single case out of thousands. It is the sine wave voltage being replicated at the output
winding. For other cases see next chapter.
As a transformer is an inductance it will behave like an inductance if we apply voltage at its primary
winding. Contrary to the common notion the secondary voltage is not dependent to the primary
voltage directly but to the changing current through the primary winding. This corresponds to the
magnetic flux generated. This is a very essential difference – it will be recalled below.
Short Pulses for Radiant Circuits 28.04.2012
Page: 4
Figure 2 - Voltage and current (sine wave)
Imagine the red line above to be the shape of the input voltage. The blue line corresponds to the
current in the primary winding.
The voltage shows a positive crest at 1/2PI and a negative crest at 3/2PI. The crest area is a point
where the voltage does not change for a short time. In fact there a positive slope converts to a
negative slope and vice versa. In-between the crests there is a point (PI and 2PI) where the change
rate of the voltage is maximum (negative slope at PI and at 2PI positive slope).
The current will show its greatest change at the maximum voltage (1/2PI) or minimum voltage
(7/4PI) respectively. In-between (PI or 2PI) the current shows its crest because from now on the
voltage will drive it in the opposite direction. The notion is that the current shows a sine shape as
well but ½ wave lengths delayed.
The output voltage is a representation of the current change rate. That is: the current change
controls the voltage generated in the output windings.
• The input voltage drives the current changes
• The current drives the magnetic flux but the flux resists like a flywheel (inertia)
• Due to the “inertia” of magnetic fields there is a delay of ¼ wave length.
• The change of flux generates the voltage at the output winding
Imagine the output wave form being a display of the change rate of the input wave form in every
minute slice of time.
The notions above cover the forward transfer of energy. Unfortunately trasformers suffer an a
reverse action as well.
Note: Apart the standard notion of a linear flow of magnetic flux there is evidence that magnetic
fields propagate in vortex shape. So please understand that the standard science presents a
simplified thinking model only.
Figure 3 - Magnetic vortex
Please read the very interesting booklet “The secret world of Magnets” by Howard Johnson
Short Pulses for Radiant Circuits 28.04.2012
Page: 5
2.3 Lenz’s Law and Other Laws
If at a transformer the load draws current on the secondary winding it intervenes with the flux as
well and reduces the inductance at the primary winding. Thus current changes happen faster at the
primary side and the current increases as well. This behavior is called Lenz’s law and corresponds
very well to the thermodynamic laws employed by standard science (conservation of energy).
Unfortunately the thermodynamic laws are based on the notion that we have closed systems. These
were invented in the 19th
century in the times of Mr. Carnot. He was the first who measured the heat
energy of input (coal) and compared it to the heat loss and the usable energy on the shaft of the
flywheel. He proved that the input energy corresponds very well with the sum of the output.
Fortunately nature does not know closed systems at all and does not care for scientific notions. In
fact the idea of a closed system is a simplification in order to grasps some details – but SOME details
only.
For understanding open and closed systems imagine the following story:
You are a modern scientist and you decided to travel by ship. Everybody knows that a ship is a closed
system and you need oil in order to drive its hull through the water. You know that the energy
entered in the engine corresponds to the sum of thermal losses (exhaust, engine cooling) and the
shaft energy being used to move the ship. In the end ALL your energy will be transformed into heat.
This is called entropy and it is a low of nature. No doubt left! Other disturbances are of negligible
magnitude.
But there are incurable guys who ignore all your knowledge and do very silly things. They build so
called sail boats. They dare to account for negligible side effects barely measurable at a motor ship.
Of course they invest energy for setting the sails – poor guys! Look how they sweat working by their
own hands! Unfortunately - shortly after - these mad brains pass your motor ship with ease.
They obviously use an open system provided by creation but being neglected by science. They make
use of an energy system being outside of Carnot’s enclosed steam engine. These outside energies will
interfere in minute extend with the closed systems but perform extremely well if we open the stuffy
chamber of Carnot’s chamber.
Similar to Carnot Lenz’s law is one pane only of the real crystal. This pane focusses on a closed
system only. Utkin, Zilano and others show additional panes (i.e. cw/ccw secondary, one short
circuited).
Short Pulses for Radiant Circuits 28.04.2012
Page: 6
2.4 Transformers – Pulse Operation
I we talk of short pulses it is self-evident that we have no sine shape but something like a square
wave. For initial consideration a square wave of 50% duty cycle will suffice in order to study the basic
behavior.
Figure 4 - Pulsed transformer
We recall:
• The voltage jumps between high and low voltage (dotted line = 0V) [a)]
• We expect the current to increase and decrease on a regular basis. Within the operation area
of the core the current change will be linear (see green graph below).[b)]
• The current slope will generate a low voltage at output winding (increasing slope = positive
voltage / decreasing slope negative voltage).[c)]
• When the voltage changes the polarity there is a sudden change in current change as well
and the output voltage will show a very short peak direction. (d)
Recall the notion above: “Imagine the output wave form being a display of the change rate of the
input wave form in every minute slice of time.” It is a kind of “accelerometer” showing the speed
of change of the voltage.
It is important to note that the voltage of the short peak is of course dependent on the turn ration
n1:n2 but is dependent on the current change as well. Sudden changes in current change determine
the output voltage considerably.
We see that sine wave mode is a very special case for a transformer. We need to overcome this
simplification in order to understand the behavior of other wave forms. Exactly this fact shown above
gives several degrees of freedom in order to create very different circuits for pulse generation.
a)
b)
c)
d) b)
c)
d)
Short Pulses for Radiant Circuits 28.04.2012
Page: 7
2.5 Pulses for Radiant Circuits
Conforming Tesla’s notion pulses initiate radiant activities beginning with 20 kHz and above. If we
want to follow tesla we should generate such pulses and not try any short cut. Short cuts often force
us to return later thereto and go the predefined way.
The frequency of 20 kHz corresponds to a frequency period of 50 µs. The pulse time corresponds to
the half period time = 25µs!! This seems not to be true at brute force sparks with fantastic light
effects. These sparks can’t be silent because of intermittent release of enormous shocks to the air.
Tesla mentioned again and again that the spark gaps need to be “thoroughly adjusted”. Depending
on the specific circuit the sparks will be conforming the requirement above (<25µs). Tesla used
quenched spark gaps in order to get pulses short enough and in precise sequence.
The pulsed operation mode above shall not be confused to another operation mode where
the sparks follow the oscillations of the tank circuit. In the latter case they might be AC as
direct image of the tank frequency. But we will focus here to the short DC pulses.
2.6 Effect of Pulse Width
Conforming the standard theory every regular shape of wave form can be synthesized by proper
mixing of sine waves of different frequency and amplitude. Conversely a given pulse shape can be
examined for content of sine frequencies. These intrinsic frequencies are real because tank circuits of
adapted resonant frequency can be excited.
The facts mentioned above can be derived in a highly mathematical manor (invented by Mr. Fourier)
but it can be explained by a simple graph as well.
Please note that the graph below is an example only. It is not a true representation of
different wave forms discussed in chapters below.
Modern scopes often can do the Fourier math for a waveform recorded in order to display
such a graph directly along with measurement functions.
Figure 5 - Fourier transformation
This representation above shows the frequencies found in a specific wave form. Every vertical blue
line represents a certain frequency, amplitude and amount of energy contained in the specific signal.
Short Pulses for Radiant Circuits 28.04.2012
Page: 8
The most left blue bar represents the basic frequency of the pulse – being a sine wave as basic
component. More frequencies are found – all sine waves which add to the basic frequency in order
to form the specific wave form of the pulse.
Now imagine the red vertical line to represent a frequency of 20 kHz (pulse 25ns). Tesla states that
our pulse should comply. All components at right hand side from the red line will comply and all at
left hand side will not comply.
Conclusion: The five frequencies at left hand side waste a considerable amount of our pulse energy
not being part of the radiant party.
In order to overcome this loss of energy the input signal needs to be increased considerably. The
smart way would be to generate pulses short enough.
Short Pulses for Radiant Circuits 28.04.2012
Page: 9
3 Pulse generation With the notions above in mind we can proceed to specific methods of HV pulse generation including
an evaluation of their performance. All setups below make use of a pulsed HV transformer and the
focus is on the method to kick it in the right way.
3.1 Pulse transformer in current mode
This is the standard ignition technology in automotive systems. Let’s have a look to the electronic
controlled variant directly. The usual winding ratio of an ignition coil is 1:100.
Figure 6 - Automotive ignition system
Recall “Figure 4 - Pulsed transformer” above -> first pulse.
• The transistor switches the ignition coils primary to ground and enables the current to flow.
• The current will increases in a linear manor up to 5 or 8 A. Along the current increase the
magnetic flus increases (Imagine an accelerating flywheel).
• Along the current increase the output coil will generate a moderate negative voltage being of
no practical use or disadvantage.
• In the very moment when the ignition spark is requested the transistor will open the current
path. The current is violently forced to stop flowing.
• The energy stored discharges via the spark plug.
The output voltage is dependent on the winding ration, the transistor switch time and the last value
of current flowing.
Unfortunately it is not easy to switch a transistor off because of some tradeoffs being connected with
the transistor itself.
• The BE junction contains a small capacitor and switching the base to ground is no fast
switching.
• Additionally there is a CB capacitance contained as well. Steep increase of collector voltage
(intended at ignition coils) adds some current to the base putting an extra demand on the
base driver.
• Transistors get lazy if they much collector current and much lazier if they get too much base
current. The tuning of transistor is not trivial. Their operation needs to be done conforming
their specification. It is easy to get a transistor vibrate somehow. But if we intend to get it
cool and fast, the facts mentioned above needs to be considerate. Let’s assume that our
transistor needs about 5µs in order to shut down 5 amps (corresponds to a slope of 1
amp/µs)
High Voltage
Short Pulses for Radiant Circuits 28.04.2012
Page: 10
Unfortunately it is worse:
The automotive ignition was invented by Tesla as well and he definitely knew what he did. The
automotive ignition system is a current employing system optimized for energy transfer. A gas
mixture needs a certain amount of spark energy in order to start a reliable combustion and it needs it
for a relatively long amount of time. The high voltage is necessary for first spark ignition only
followed by a plasma arc burning at about 600V. The sparking time is about 500µs up to 1ms.
These advantages for a gas combustion convert to disadvantages if employed for short radiant
pulses. The main disadvantage is that the ignition coil needs a certain amount of primary current in
order to produce high enough voltage if the current is interrupted. The stored energy at this time of
interruption is high enough in order to feed a long burning time of the plasma. Apart that there is a
vast amount of energy left if the spark interrupts so final oscillations will occur. Sometimes a second
reverse spark will occur. Additionally the long spark time is far away from 25 µs.
3.2 Spark gaps – tesla mode
Tesla in his time had no semiconductors available and vacuum valves arose in the 19th century long
after his groundbreaking discoveries. It is interesting to note that Tesla never used the automotive
ignition scheme at his radiant circuits.
Figure 7 - Tesla's pulse technology (example)
He kicked the primary coils with short HV voltage pulses. This technology is not an amperage
technology like automotive ignition systems but a high voltage technology. Nevertheless he made
use of the method of current change - BUT BEFORE high currents build up. The focus here is high
voltage / short pulse and NOT high energy and long burning time.
If we recall “Figure 4 - Pulsed transformer” it is not essential if we get the current increased suddenly
or stopped. Tesla shoots a small charge out of the primary capacitor to the coil. Because of high
voltage he initiates a very steep current slope. He does not need much current but just the current
slope for short time. There spark stops earlier and the rest energy in the coil is much less compared
to the automotive ignition system.
The notions above apply to parallel or serial spark gaps. The final effect is the same. In fact it is quite
easy to get pulses below 100µs. Tuning is quite easy: capacitance and voltage.
Short Pulses for Radiant Circuits 28.04.2012
Page: 11
3.3 Pulsing oscillating coils
Especially at this circuit above, repetitive sparking should enhance the oscillation of the coil and NOT
decrease oscillations. If we pulse brute force at any deliberate time asynchronously we may hit the
coil in a moment where we cancel the oscillating energy within the coil. Sudden stop of oscillation
will occur and restart at the next spark. At extreme brute force any state of the resonant coil will be
overridden and reset to a new oscillating sequence.
This document will not cover more details regarding synchronous sparking or multi sparking. It is felt
to be important mentioning this detail along Tesla’s circuits. For more details see i.e. the animation
here.
3.4 Pulsing Don Smith circuits
Don Smith rearranged Tesla’s technology because he had available modern electronic components.
So the primary pulsing brings no additional notions.
Excursus:
But Don used another pulse system not being obvious. It is corroborated that Don - at end of
his life - admitted that his technology may function without resonant coils. If that is true then
the magic happens in the capacitors being pulsed severely. Once again we need pulses as
short and high as possible.
His resonant coil performed exactly that: Pulses of 0.5µs (corresponds to 1 MHz -< pos. and
neg. cycle rectified) or less through the diodes and high voltage onto capacitors. It works with
or without cw/ccw coils! But it is essential to have fast switching diodes – 10% of pulse time
recommended. And of course we need capacitors being able to admit such pulses without
being a low pass filter for mains frequency only.
3.5 Capacitor Discharge Ignition (CDI)
After discussing different systems for pulse generation there is one left and surprisingly – it is
currently used for automotive racing applications and motorcycles as well. It is a modern replication
of Tesla’s technology. The circuits are simple and understandable easily – much more if someone
dealt with Tesla’s circuits before.
For automotive applications a short spark is a severe drawback. They overcome this disadvantage by
firing multiple sparks being short and of very high energy. (up to five). If we omit the multiple sparks
the CDI circuit gets more easily and will perfectly fit to radiant circuits.
Let’s take the standard circuit from Figure 6 and replace the 12 V battery voltage by a capacitor
precharged to 300V DC. (The transistor should be a high voltage type).
High Voltage
300V
Short Pulses for Radiant Circuits 28.04.2012
Page: 12
If we switch the transistor on the capacitor will discharge within a short time through the primary
winding.
The conditions changed considerably compared to the standard ignition circuit:
• The basic circuit corresponds to Teslas’s basic circuit except the switch element is now
related to ground. Pluralities of other configurations are possible but this is best for
explanation.
• We get the spark just short after the trigger signal and we deed not precharge the coil
before.
• Because of the high input voltage the current rise is very steep and exactly this converts in
the end in a very high voltage at the output. Please note: We don’t need high current in the
primary winding but high current increase. At the end of the HV pulse at output we have
much less energy stored in the magnetic field.
• The transistor is not loaded with so much current like before in the standard ignition circuit.
• The capacitor charge and voltage determines the pulse time for a given inductance.
• The switch off speed is irrelevant because the charge of the capacitor will be exhausted
before we shut the current path.
• A too high base current speeds the switch on time up, while slowing down the switch off
time - but the latter is irrelevant (see above)
• The transistor will switch very fast ON because it will deal with a minute current at this time
– the coil prevents instant high current.
• The best news is: the pulse time being at output being less than 80 µs at automotive CDI
ignition systems and this value can be drilled down by proper tuning.
• Standard ignition coils can be used as long the output voltage is not driven higher than max.
ratings.
Please understand that this example explains the basic principle only and is not a
thorough suggestion for easy copy and paste. You are requested to understand the
matter and develop own circuits for your special application.
In Summary: A CDI circuit is a simple circuit producing short high voltage pulses with fewer
implications compared to a standard ignition circuit being based mainly on current flow.
And please note that CDI circuits follow Tesla’s circuits.
The question is left: How to recharge the capacitor above?
(Schematic generated with KiCad)
Here is one of a plurality of different possibilities.
Short Pulses for Radiant Circuits 28.04.2012
Page: 13
The recharge is performed by L1 / D1. If the transistor is in standby state the capacitor C2 will be fully
charged. In the moment of discharging C2 through TR1 the coli L1 will block a sudden recharge. This
is essential in order to not recharge C2 too early. (Else we get a standard automotive circuit and
destructive long pulses.). After spark event and the transistor being inactive the coil L1 gets active,
the current flows to C2 up to full charge (HV input voltage).
The good news is that an inductance behaves similar to a flywheel. The current will not stop if C2 is
fully charged to the voltage of C1 but will be charged about twice the HV DC voltage at input. D1
blocks the current from flowing back to C1. Only the very first HV pulse at output will show less HV
and will be shorter.
Properly tuned this circuit will recharge C2 at a big range of frequencies to a very constant voltage at
C2.
The HV generation (300V) is not discussed here. Some suggestions can be found in the linked
schematics below or at good sites from Tesla coilers.
The following links show some schematics for CDI circuits. Study them and find your
genuine application.
An example for a CDI circuit:
another
another
another
another
simplest circuit scroll down
Application note from STM
another
BTW: see the pic there. Left normal spark and right hand spark with prallel
cap. There we see what Tesla stated regarding the cap before spark gap..
3.6 Nanosecond Pulses
The text above focusses on simple pulse generation not shorter than some µs. Research and laser
applications require pulses far shorter in the range of nanoseconds or picoseconds. It is important to
know that electronic parts can do it but this is no standard technology. They use step recovery
diodes, nonlinear transmission lines or cascode connection technology. Her an example: A 500V
nanosecond pulse generator using cascode-connected power MOSFETS.
~o0o~