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Author Topic: New Lasersaber build, super-Joule-Ringer variant  (Read 53261 times)
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img  PhysicsProf
New Lasersaber build, super-Joule-Ringer variant « on: 2012-05-03, 03:09:11 »
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  Here are recent vids by these Lasersaber and Lidmotor -- whose creative work I admire -- and a most interesting Joule-Thief variant:

lasersaber jouleringer2 :  http://www.youtube.com/watch?v=homZvbKZHlU   and http://laserhacker.com/SuperJouleRinger2.html

His web site laserhacker.com show what E-cores and bobbins he used; I've ordered some.
He displays 20 gauge bell wire, shows on vid as from Utilitech, says it costs $4 for 65 feet.  He recommends this, but I can't find this on-line, this particular wire.  Anyone know of a source?
Also -- what transistor did he use?

lidmotor build of above:  http://www.youtube.com/watch?v=o0fCQghOQ-E&feature=uploademail

Found the EF.com thread:
http://www.energeticforum.com/renewable-energy/7051-joule-ringer-39.html

Lidmotor's comment:
Quote
@Lasersaber & All
I replicated the "Super Joule Ringer 2.0" today and made a video of it. I built the transformer using the bell wire and used that Lowes 40 watt LED bulb.
All I can say is that this is very impressive. I just wish that I understood how the circuit worked.

Super Joule Ringer 2.0 -- My Replication - YouTube

Cheers,

Lidmotor

Apparently, the efficiency has not yet been measured, nor do I see any measurement of the output frequency yet.  Such measurements would be worthwhile.
 One of the vids mentions that this circuit could be used as an inverter circuit, DC to AC...

   
img  muDped
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #1 on: 2012-05-03, 03:39:39 »

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The LED Bulb which they're illuminating is a "Forty Watt
Equivalent" which is rated at 8.6 Watts actual power
consumption.  While the circuit is indeed an unusual
configuration with the lamp inserted into the base
drive line; it isn't producing any unusual level of output
power.  Probably something less than 8 Watts at the
lamp with about 9.6 Watts DC input.

I agree, they do inspire a lot of experimenters with
their projects and their videos.



---------------------------
For there is nothing hidden that will not be disclosed, and nothing concealed that will not be known or brought out into the open.
   
img  PhysicsProf
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #2 on: 2012-05-03, 03:43:24 »
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  Good point, Dumped.

  I like this replication by mopozco, note that he uses a toroid (rather than cylindrical geometry):

http://www.youtube.com/watch?v=0eWhB76toq0&feature=youtu.be

and his clear circuit diagram:
   
img  Farmhand
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #3 on: 2012-05-03, 04:02:07 »
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Wow those transistors say they can take 7 amps of base current.
I guess a few lights could be it like that then. I find with pulsed setups if they make noise
or heat they are less efficient. And higher wattage stuff is harder to light properly as well.

Its hard to beat the light from a 100 watt incandescent with the correct voltage across it
using regular AC. Not easy to store the juice to power them for long without the grid though.

The heat  :P
   
img  PhysicsProf
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #4 on: 2012-05-03, 15:49:13 »
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  A replicator peanutbutter291 provides a first estimate of Power out versus Power in with the New JouleRinger circuit, his build of course.
http://www.youtube.com/watch?v=Hw_-2c19YwI&feature=g-all-u

He uses a light meter to first verify that a 7.5 W LED bulb (120V bulb) puts out 490-500 lumens, as advertised with this particular bulb.
Then he drives 7 bulbs, at full output this would be 7 x 7.5W = 52.5W.  

First run, he gets 85% of full brightness, so 52.5W x 0.85 = 44.6W is his estimated Pout.
The power supply is at this time providing 1.55A at 12V = 18.6 W input.
Efficiency is roughly 44.6/18.6 ~ 2.4; interesting though still a rather crude measure at this point.

Second run, with choke added in series with the load,
 he gets 78% of full brightness, so 52.5W x 0.78 = 40.95 W is his estimate Pout.
The power supply is at this time providing 1.52A at 11.5V = 17.48W input.
Efficiency is roughly 41/17.5 ~ 2.3; again interesting.

I show from his (long) vid the calculations of Pout and Pin, along with his revised circuit diagram.
Note that he first adds bias through a resistor to the base, to get the ringing started, and for the second run he adds a choke.
   
img  Farmhand
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #5 on: 2012-05-03, 19:15:04 »
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It's always the same story though. Lights and dodgy measurements. I didn't see him measure the power consumption from the AC line
to determine what they actually use to produce the light reading. At about 14:2 mins when he picked up the lumen meter it went up about 20 lumens looked like.
Lumen meter is all over the place.

I'm not sure how light meters work, but he measured the light from one light powered from the line then measured the light from at least two lights powered from the joule ringer.
I don't trust the readings from the power supply either.  All in all it looks rather normal without proper measurements.
Anyone know what circuitry is in the bulbs ? And if pulsed power would be more efficient for them ?

One thing about the circuits that use a field collapse and don't keep the output voltage down is heating of the transistor problems.
Does this circuit overheat the transistors with a couple of amps input ? Not much use if they overheat.

Neat and different circuit though. interesting.

Cheers
   
img  Hoppy
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #6 on: 2012-05-03, 19:29:33 »
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Interesting video. A couple of thoughts on this: -

Can it be assumed that the lumen level has a linear relationship to the power consumed by the LED lamp load, especially when approaching full rated light level? I know that insofar as mains filament lamps are concerned, the relationship is not linear.

Were all the lamps running at the same lumen level, as this was not demonstrated? My experiments show that when connecting additional lamps, lumen levels vary across the lamps.

Hoppy
   
img  BEP
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #7 on: 2012-05-03, 21:55:57 »
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LEDs used in lighting are far from linear. Even the best only have a narrow area with some linearity.

The light meter is an extremely poor way to obtain a measurement of power.

On top of that, LEDs react more easily to spiky DC, especially approaching radio frequencies.

Looking at the schematic/sketch, it is drawn out of kilter but is nothing special.
   
img  PhysicsProf
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #8 on: 2012-05-03, 23:14:16 »
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  We agree that the power measurements especially Pout are crude at this stage.  Still interesting IMO.

After working all night, he notes, peanutbutter 291 adds this at ou.com:
Quote
First, I want to again thank Lasersaber and his Super Joule Ringer 2.0 design.  This would not be possible without that design being offered.

Introducing the SJRC!!  Super Joule Ringer Charger!
I have uploaded a video of a 1.0 version of the SJRC I'm happy with.  I'm separating this in terms of a different circuit, as it bares little resemblance and function to the original LS design.

This circuit, will drive 7 - 7.5w 120v LED's at a measured 85% brightness AND charge batteries at the same time!!!  All the aspects are shown in the video and I've included  a current schematic with all the values.  I must point out that the shown values are totally "tuned" for 7 bulbs and this will not work "exactly" the same otherwise.  Caps across the Pri and Sec are Required and L3 must be a certain value based on load.  I mention cap values for 1 bulb and no L3 is needed.

I only had batteries to charge 3.7 and 9v currently so I'll get more cells to find the optimal charge Voltage for batteries (guessing 48v range).

I'm happy with this circuit as it runs very efficiently, near full output, dual function of charging and all for 18.2w!? So, 7 x 400 (-25 for error) Lumens = 2800 total lumens for 18.2w ---153 lumens per watt!!  That's even with Cree's newest and world's most efficient LED.  But we can charge batteries too!?!?
Hope this helps someone replicate or find more improvements to this.

Video http://www.youtube.com/watch?v=LCfeuzMyfdI&feature=youtu.be

Thanks, PB
   
img  PhysicsProf
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #9 on: 2012-05-09, 22:31:17 »
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Just posted this on the aforementioned EF thread:
 
Following on the work by Lasersaber, Lidmotor, Peanutbutter and Burgess in particular, my son and I constructed a "light-box" to permit repeatable measurements using TWO light meters -- and a triplet of power and voltage meters to monitor input power.   Pls see attached photos from my home
electronics bench today.

I found that the meters agree quite well -- one of them is the SAME as used by Lidmotor in vids (orange-color around it).   The black one is cheaper on Amazon. 
However -- the meters do not measure LUMENS but rather Lux -- as would be expected actually.  (See wiki http://en.wikipedia.org/wiki/Lumen_%28unit%29 )

Quote
The difference between the units lumen and lux is that the lux takes into account the area over which the luminous flux is spread. A flux of 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square metres, produces a dimmer illuminance of only 100 lux. Mathematically, 1 lx = 1 lm/m2.

A source radiating a power of one watt of light in the color for which the eye is most efficient (a wavelength of 555 nm, in the green region of the optical spectrum) has luminous flux of 683 lumens. So a lumen represents at least 1/683 watts of visible light power, depending on the spectral distribution.

So we have to be cautious regarding colors, also the difference between lux measured on the meters and lumens.

So I ran various "bulbs" in the box and kept track of the input voltage, input power via two meters, and lux via the two light meters.  As long as the bulbs were designed to put out light more-or-less isotropically (in all directions -- not beam-like), I found a GOOD correlation in my box between lumens and the measured lux on the meters.

That is -- I assumed the lumens as listed on the packaging with each bulb is reasonably accurate.  I found that the voltage in town varies from about 117 VAC -- then the power on the meters agrees well with the rated power on the bulb -- and about 124.7 VAC.  The lux meters show a sharp RISE in output lux when the voltage in town jumps UP.  (I was surprised the voltage varies so much... good thing I'm keeping track of it!  so I can make sense of my readings.)

So, when the power for a 40 W bulb showed 42.5 W with the higher voltage, I made two separate measurements of lux output, and I assume the given lumens output scales roughly linearly for a small change in input voltage.

Likewise for the various bulbs, 90W, 100W incandescent; 13 W fluorescent; and 9.5 W LED bulb.   

I found that to within a few percent, I could find a conversion factor between what I read on the flux meters IN THE LIGHT BOX and lumens as given on the packaging!  That is, I was able to calibrate the light-box-plus-light-meters system.  Without given all the data here (tedious, its all in my logbook) -- here is the conversion:

Lumens = 0.059 * Lux   (+/- about 7% with the various measurements involved) with my light-box.

This is actually the value using just the top watt-volts-kW-hour meter (it is cheaper and I like the increased digits for kW-hours)  AND the cheaper black light-meter.   The conversion factor found by averaging both power-meters, and also averaging the light meters is about the same, so I'm simplifying measurements by focusing on two meters, one for input power and one for output light.  (But I do have redundancy to check things; part of my scientific training I guess... ;)  )


   I would be leary of using this system to try to establish ou, there are much more reliable measurements IMO, but -- this is a very interesting way to compare lumens/watt for various bulbs AND for various circuits -- like the SJR -- for the same bulb.

Peanutbutter and Burgess pls note -- one may get more lumens/watt (Lm/W)  due to higher frequencies in the output circuit, for example; that is, higher Lm/W does not NECESSARILY MEAN that you are getting more POWER in the output circuit, it may just be there is more efficient light -output than is rated on the bulb for 60 Hz.
   
img  muDped
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #10 on: 2012-05-10, 19:49:19 »

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Your tutorship is so very valuable because far too many in the Experimenter
Community have no idea how to implement the systematic scientific process.

Some of the discussions at EF are examples of foolishness and even reckless
attempts to satisfy curiosity.

Granted, striving to stamp out ignorance is a steep uphill endeavor.

You're showing the way very effectively - let's hope your work goes viral!



---------------------------
For there is nothing hidden that will not be disclosed, and nothing concealed that will not be known or brought out into the open.
   
img  Farmhand
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #11 on: 2012-05-11, 21:07:29 »
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Hi Guys, I was wondering. If I use a CFL to measure the load power why can't I just rectify
the transformer output to make 240 volt DC to feed the CFL ? Then I can measure that.

Seems like a decent way to go since the CFL's internal circuitry rectifies the AC anyway.

Here is a rough video I made of my existing transformer lighting a 25 watt incandescent globe.
I think it's almost as efficient as it gets before being too close to call.

http://www.youtube.com/watch?v=7pzqxQwxVGA

The voltage across the load is a bit higher than 240 and the input power seems very close to
the rating of the bulb minus half the idle power. It appears that a good portion of the idle power
goes to the load when the load is applied.

Please forgive the mumbling and repetition, I'm not trying to bling anybody.  ;D

I guess I will need to measure the input/output two ways with the resistor method as well.
So a question is what resistance would be best to use for measuring the input current/output current as direct current.

I think I should be able to use all DC current measurements, if I use a CFL load

The same could be done for LED globes that can use DC. I think simplifying measurements is the way to go.
And especially with CFL's I can't see it affecting the device in any way that is not already done by the CFL.

Also, if I use series capacitors on the transformer AC output I can fairly accurately control the maximum output
at a given frequency, as well as do some interesting things by varying the PW. After some experiment I installed
a small non polarized capacitor between the two primary coil negatives (mosfet drains). Intuition told me to do that
but now I see it done in other schematics so I guess it must be common practice.  :-[ No one told me it was a good idea.

I think I might have a fraction too much dead time or something, because of all the spikes. Those spikes can be serious and
I think caused arcing in my 240 volt sockets at times depending on frequency and such.

Any thoughts.

Cheers

P.S.Also My secondaries are a bit mismatched so that might be causing some imbalance problems, I need to even them up and
add a couple of layers to increase the unloaded low frequency voltage to about 265 volts or so..
   
img  Farmhand
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #12 on: 2012-05-12, 13:02:02 »
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Well I did some measurements with a CFL and direct current. I rectified the transformer output
into a 1 uF microwave capacitor then just powered the CFL from that and measured the voltage
across a 0.1 ohm 5 watt resistor in the negative line between the cap and the FWBR. With 242.5 volts DC
across the capacitor the 15 watt (rated) CFL used 52 mA indicated by 5.2 mV across the 0.1 ohms.
Which I make as 12.61 watts.  I'm hoping these calculations are correct at least.

With 261 volts across the cap the 15 watt (rated) CFL used 53 mA so 13.83 watts, still under the 15 watts.
but that was not hot, maybe when they heat up they use more power.

A 25 watt incandescent lamp with 230 volts DC uses 112 mA = 25.76 watts

Interesting. In all cases my setup apparently used an additional 5 watts or so, by using the 0.1 ohm resistor
to determine the current from the battery.  Oh well.

I think it might pay to determine just what power the lamps actually do use. Real time.

I do think the incandescent can be lit with 240v AC cheaper than with DC, but the light might be a bit less too.

Cheers  

P.S. These were just a test of the power use of the lamps, mainly.

..
   
img  PhysicsProf
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #13 on: 2012-05-12, 15:21:33 »
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I like EXPERIMENTS --thanks Farmhand for your work and for reporting it.

A new approach has emerged in the last week or so,
http://www.overunity.com/12340/joule-lamp/msg322288/#new

Lynxsteam writes:
Quote
The Joule Lamp is a takeoff on the work many here have been doing.  Its a cross breed between Laser Saber's Joule Ringer 2.0 and a tesla coil.  I liked the simplicity and elegance of a transformer with a transistor that can light 110 volt lighting very efficiently.  I didn't like the buzz and the difficulty in finding the right E core transformer.  The simplicity and quietness of an aircore coil is convenient.

I wonder -- how much of the effect here is simply air-core transformer, and how much is due to a Tesla-coil (resonance) effect?
Anyway, his latest vids are very informative, intriguing -- links provided in this short thread.
   
img  PhysicsProf
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #14 on: 2012-05-12, 16:18:32 »
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Quote
wiki:   A Tesla coil transformer operates in a significantly different fashion from a conventional (i.e., iron core) transformer. In a conventional transformer, the windings are very tightly coupled and voltage gain is determined by the ratio of the numbers of turns in the windings. This works well at normal voltages but, at high voltages, the insulation between the two sets of windings is easily broken down and this prevents iron cored transformers from running at extremely high voltages without damage.

With Tesla coils, unlike a conventional transformer (which may couple 97%+ of the fields between windings) a Tesla coil's windings are "loosely" coupled, with a large air gap, and thus the primary and secondary typically share only 10–20% of their respective magnetic fields. Instead of a tight coupling, the coil transfers energy (via loose coupling) from one oscillating resonant circuit (the primary) to the other (the secondary) over a number of RF cycles.

As the primary energy transfers to the secondary, the secondary's output voltage increases until all of the available primary energy has been transferred to the secondary (less losses). Even with significant spark gap losses, a well designed Tesla coil can transfer over 85% of the energy initially stored in the primary capacitor to the secondary circuit. The voltage achievable from a Tesla coil can be significantly greater than a conventional transformer, because the secondary winding is a long single layer solenoid widely separated from the surroundings and therefore well insulated, Also, the voltage per turn in any coil is higher because the rate of change of magnetic flux is high at high frequencies.

With the loose coupling the voltage gain is instead proportional to the square root of the ratio of secondary and primary inductances. Because the secondary winding is wound to be resonant at the same frequency as the primary, this voltage gain is also proportional to the square root of the ratio of the primary capacitor to the stray capacitance of the secondary.
[/b]
   
img  muDped
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #15 on: 2012-05-12, 18:06:31 »

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The wiki article illuminates several characteristics of the Tesla Coil but
it fails to clarify how the primary is tuned to the secondary resonance.

The secondary winding of the Tesla Coil is essentially a helical antenna.

The primary winding is postioned at the lower end of the secondary
to enable "end feed" of the helical antenna at its low impendance
point.  At resonance the secondary functions as a 1/4 wave RF
"transformer" where the upper end represents the high impedance
point with voltage maximum and current minumum.

The capacitance in the primary circuit serves both as an energy storage
reservoir to intensify the disruptive discharge at the spark gap and as
a tuning capacitor to tune the primary to the secondary resonant frequency.
Some Tesla Coils are constructed with a tapped primary to accomplish the tuning.

The top end of the secondary may also be fitted with a "top hat"
capacitor to intensify the high voltage arc/corona.

It is truly amazing what Tesla was able to achieve with such primitive means
of generating radio frequency oscillation.


---------------------------
For there is nothing hidden that will not be disclosed, and nothing concealed that will not be known or brought out into the open.
   
img  Farmhand
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #16 on: 2012-05-12, 19:33:15 »
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Quite right Dumped, as can be seen when tuning a Telsa transformer the secondary/extra coils
need only be excited by the bottom end.

It's also worth noting that Tesla's three coil system with the extra coil can use a "coupling transformer"
as in a tightly coupled (primary - secondary) air core transformer with a very loosely coupled helical resonator.

The helical resonator in the three coil arrangement is properly "end fed" as Dumped put it.

Cheers
   
img  PhysicsProf
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #17 on: 2012-05-13, 04:46:49 »
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Good points, Dumped and farmhand, and I'm still learning about Tesla coils.
Quote
The capacitance in the primary circuit serves both as an energy storage
reservoir to intensify the disruptive discharge at the spark gap and as
a tuning capacitor to tune the primary to the secondary resonant frequency.
Some Tesla Coils are constructed with a tapped primary to accomplish the tuning.

OK -- but in the case of Lynxsteam, he does not have a spark gap...  so how could his system function as a Tesla coil?  (perhaps not tuned very well....)

   He did tap his primary windings to get a "brighter CFL" output, empirically.

I attach his schematic, and photos from one of his vids which I pulled together for discussion.
Note the green wire is the tapped primary; the 30 AWG secondary is beneath the white plastic tubing holding the primary (so the secondary is not seen).
   
img  Farmhand
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #18 on: 2012-05-13, 05:46:31 »
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I'm no expert, I can only give my observations as I see them, my opinions and insights.
I don't think a spark gap is necessary for a Tesla transformer, Tesla himself used mercury interrupters
amongst other things. The transistor can take place of a spark gap. Tesla used both AC primary circuits
and DC primary circuits. The main thing is to get resonance with the maximums and minimums of voltage
in the correct place for the type of system that is being used, 1/4 wave resonance mostly.
A bipolar transformer would have two 1/4 wave structures each side of center or a 1/2 half wave, with a  node
in the center which can be fixed to ground.

Cheers
   
img  exnihiloest
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #19 on: 2012-05-13, 11:33:35 »
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Quote from: Farmhand on 2012-05-13, 05:46:31
I don't think a spark gap is necessary for a Tesla transformer, Tesla himself used mercury interrupters
amongst other things. The transistor can take place of a spark gap.
...

You're right, we just need an interrupter able to rapidly switch the primary circuit on and off from a DC source, or to use an AC source. Nevertheless there is no logical hope to get free energy by this conventional way.
There are many alleged OU devices using sparks: Gray's tube, Kapanadze, plasma balls... We can see a spark gap as a "gate" open to the environment (ZPE vacuum or anything else) and so, if we are searching for new physics, spark gaps could be a much better way to get anomalous results, than conventional switches or inverters.
   
img  GibbsHelmholtz
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #20 on: 2012-05-16, 14:13:27 »
Group: Guest
[quote ]

wiki:   A Tesla coil transformer operates in a significantly different fashion from a conventional (i.e., iron core) transformer. In a conventional transformer, the windings are very tightly coupled and voltage gain is determined by the ratio of the numbers of turns in the windings. This works well at normal voltages but, at high voltages, the insulation between the two sets of windings is easily broken down and this prevents iron cored transformers from running at extremely high voltages without damage.

With Tesla coils, unlike a conventional transformer (which may couple 97%+ of the fields between windings) a Tesla coil's windings are "loosely" coupled, with a large air gap, and thus the primary and secondary typically share only 10–20% of their respective magnetic fields. Instead of a tight coupling, the coil transfers energy (via loose coupling) from one oscillating resonant circuit (the primary) to the other (the secondary) over a number of RF cycles.

As the primary energy transfers to the secondary, the secondary's output voltage increases until all of the available primary energy has been transferred to the secondary (less losses). Even with significant spark gap losses, a well designed Tesla coil can transfer over 85% of the energy initially stored in the primary capacitor to the secondary circuit. The voltage achievable from a Tesla coil can be significantly greater than a conventional transformer, because the secondary winding is a long single layer solenoid widely separated from the surroundings and therefore well insulated, Also, the voltage per turn in any coil is higher because the rate of change of magnetic flux is high at high frequencies.

With the loose coupling the voltage gain is instead proportional to the square root of the ratio of secondary and primary inductances. Because the secondary winding is wound to be resonant at the same frequency as the primary, this voltage gain is also proportional to the square root of the ratio of the primary capacitor to the stray capacitance of the secondary.

[/quote]


I think I'm starting to see what a Tesla coil is.  Seems like he described his coil as a transmission line.  The input gives a voltage when primary turns on, wave propagation start out with wire as inductance and between turns as capacitance.  If so, the length of this transmission line is the actual wire length and not coil length?  Hm...
   
img  exnihiloest
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #21 on: 2012-05-16, 20:35:16 »
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It's not well explained on wiki. The "loose coupling" is only an apparence. They say: "the primary and secondary typically share only 10–20% of their respective magnetic fields". This is true, the coefficient of coupling is of that order. But when the circuit is in resonance, the circuit is couping near 100% for the energy transfer although the coupling coefficient is still "only 10–20%", and so "with significant spark gap losses, a well designed Tesla coil can transfer over 85% of the energy initially stored in the primary capacitor to the secondary circuit".

It is perfectly explainable and modelizable in electronics. The equivalent schematic for two coils weakly coupled, is two coils 100% coupled but with an independant inductance in series with one or the two coils. When a capacitor is added to the circuit, the impedance of the extra-inductance is canceled by the impedance of the capacitor at the resonant frequency, and so all is happening as if there was a 100% coupling.

For instance this technics is used in narrow band HF amplifiers. Each stage of the amplifier is linked to the next thanks to loose coupled coils that are tuned to the working frequency using adjustable capacitors. Near 100% of the energy of each stage feeds the next one.
   
img  muDped
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #22 on: 2012-05-17, 01:15:35 »

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Quote from: GibbsHelmholtz

I think I'm starting to see what a Tesla coil is.  Seems like he described his coil as a transmission line.  The input gives a voltage when primary turns on, wave propagation start out with wire as inductance and between turns as capacitance.  If so, the length of this transmission line is the actual wire length and not coil length?  Hm...


Aye, you're right on the mark.

It's a resonance which is defined by the propagating wave very
similar to how a transmission line stub is capable of acting as
a high Q resonant circuit.

The secondary winding of the Tesla Coil is much more akin to a
vertically polarized helical antenna which has input energy coupled
in at its low impedance end near ground.

A vertical 1/4 wave antenna is very similar to a Tesla Coil in how
the standing wave develops.


---------------------------
For there is nothing hidden that will not be disclosed, and nothing concealed that will not be known or brought out into the open.
   
img  GibbsHelmholtz
Re: New Lasersaber build, super-Joule-Ringer variant « Reply #23 on: 2012-05-17, 01:59:16 »
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Quote from: exnihiloest on 2012-05-16, 20:35:16
It's not well explained on wiki. The "loose coupling" is only an apparence. They say: "the primary and secondary typically share only 10–20% of their respective magnetic fields". This is true, the coefficient of coupling is of that order. But when the circuit is in resonance, the circuit is couping near 100% for the energy transfer although the coupling coefficient is still "only 10–20%", and so "with significant spark gap losses, a well designed Tesla coil can transfer over 85% of the energy initially stored in the primary capacitor to the secondary circuit".

It is perfectly explainable and modelizable in electronics. The equivalent schematic for two coils weakly coupled, is two coils 100% coupled but with an independant inductance in series with one or the two coils. When a capacitor is added to the circuit, the impedance of the extra-inductance is canceled by the impedance of the capacitor at the resonant frequency, and so all is happening as if there was a 100% coupling.

For instance this technics is used in narrow band HF amplifiers. Each stage of the amplifier is linked to the next thanks to loose coupled coils that are tuned to the working frequency using adjustable capacitors. Near 100% of the energy of each stage feeds the next one.



I know what you mean and I've simulated the condition you described.  It is as you said.  However, how can you explain the voltage gain on the secondary is greater than the turn ratio of primary to secondary?   If we have a perfect coupling, voltage gain obeys turn ratio.

Another thing is an LC circuit cannot have current reversal in the same coil thus giving out nodes like some Tesla coil claims. 
« Last Edit: 2012-05-17, 03:21:23 by GibbsHelmholtz »
   
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Re: New Lasersaber build, super-Joule-Ringer variant « Reply #24 on: 2012-05-17, 04:14:01 »
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If I can jump in here real quick,  I think I can shed some light on this topic.

A Tesla coil at the bottom has the primary loosly coupled magneticaly to the bottom of the secondary coil.    As a result, the bottom section of the secondary develops a small voltage by induction and this voltage then resonates the rest of the secondary coil in an unconventional way.    It's unconventional because it behaves more like a transmission line at higher frequencies, than at lower frequencies.   At high frequencies, when the length of the wire starts to approach 1/4 wavelength, the voltage builds up to realy high levels due to the high quality of a transmission line which has very low resistance if designed correctly.

I agree with what EX is saying as well:  at resonance, we can transfer ENERGY almost at 100 % minus a few losses, so just because magneticaly we are weakly coupled (10% perhaps) does NOT mean that energywise we are weakly coupled as well.    And yes, the weaker the magnetic coupling, the narrower the bandwidth in these tuned systems.  If we were highly coupled, like in a transformer, then we would have a broadband energy coupling device.  (in terms of circuit elements, the weak coupling produces an effective higher turns ratio that is much higher then the actual one, so the secondary resistance reflected to the primary is very small,  and a small resistance in a tank circuit means high Q, which translates into a narrow bandwidth filter, if that's the use.)

Bottom line: a Tesla coil is a resonant transformer with an integrated transmission line formed by the long secondary.    

You can prove this to yourselves by feeding a Tesla coil direcly from a signal generator that you can adjust, which I've done.  As you increase the frequency you get different modes and if you move the probe connected to an oscilloscope up and down the secondary you see nodes of maxima and minima, clasical transmission theory!

EM

PS.  actually, the long secondary coil behaves like an monopole antenna with reference to ground.   The only difference between a straight monopole rod antenna and the Tesla secondary is the vertical velocity of the energy is slowed down by a factor of  d / (2 pi R) where 'd' is the spacing from turn-to-turn of the secondary, and 'R' is the radius of the secondary coil.    So, since the vertical velocity is slowed down, the vertical wavelength is shorter as well, and also the resonant frequency, so as a result we can hit the 1/4 resonance mode with much lower frequencies.   However, don't think that it will radiate efficiently like a monopole antenna because it won't, and that's becasue it is poorly matched to the wavelength in space so the fields do not detach easily, and Tesla understood this very well and even coments on it.    So in a way it is a "fake" monopole antenna that does not radiate becaue of mismatch in the wavelengths.
   
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