Passive oscillator challange!

[Armagdn03]

Hello community,

I was doing a bit of meditation the other day which led me to an interesting thought / challenge, which anybody with any skills in electronics can try and take on! Not only will the concept be incredibly valuable in terms of usefulness in many applications, but also holds greater significance.

Here is the challenge,

Create a passive oscillator.

This oscillator can only use passive components, capacitors, inductors, resistors etc. Any combination or configuration will do. Examples of exotic elements might be a C-stack (four plate capacitive transformer) Bifilar coils, coil capacitors etc.

In natural settings many such mechanisms show up. Eddies in the river, the strap on my car-top carrier humming in the wind, a bottle singing when one blows across it etc.

In the electrical world I only know of one such device, the magnetron, upon which a ionized wind causes an LC cavity to oscillate in a tube like arrangement.

I would like to stay away from impedance breakdown as an oscillatory mechanism unless controllable. Therefore spark gaps, neons and what not are good, but if we can do without so much the better! I would be damn impressed if we could come up with a solution which could oscillate a wide range of currents without needing to have 3000v on the input.

We have a device (magnetron) which can do it very fast, how do we make it slower? We can model it in passive components, but the geometry is different which is what operation is dependent on! how do we do it!!!!

This is going to take a lot of creativity, this is absolutely the best group for it. Thank in advance to all who at least give it a thought.

[morpher44]

passive oscillator

@Armagdn03

T. H. Moray has some equations for this in
"Beyond the Light-Rays".

If your circuit analysis can simplify down to a basic LRC circuit, regardless of how exotic your design is, to self oscillate, you will need

R*R <<far less than> 4L / C

That is why superconductivity is of interest to the science community,
because R can be made to approach zero.

It would be ideal, however, if a design could oscillate at room temperature so that as you say -- off the shelf -- inexpensive -- passive components could be used.

I'm leaning toward the idea of making L as large as possible.
One interesting thing about coils is that there are still some unexplored geometries.
Also, there are ways of making components such that they are non-linear.
Add ferro to an inductor, for example, and the inductance is not linear .. but influenced by flux that can be imposed by other means.

Capacitors, too, can be devices that are combination capacitor and antenna. Ionize a plate and its ability to "receive" is enhanced, as
discussed in:
http://www.energeticforum.com/renewa...gy-patent.html

Tesla's Cupola for Wardenclyffe was a hybrid capacitor / antenna.
Hendershot's cylinders are hybrid capacitor / antenna.

Moray had exotic semiconductor material that may have had unusual non-linear capacitance or non-linear inductance (or both) or
may have helped ionize his antenna.

Resistance can be kept low by building things BIG .. with large
gauge wire ... if you have the funds and space and time.

[Sephiroth]

perhaps this is too obvious but what about a 1:1 transformer where one winding is connected to a dc source and the other to a capacitor.

I guess I don't understand the challenge

[Inquorate]

The challenge

The challenge as I understand it is to build a circuit that self oscillates without input from an exhaustable source like a battery.

http://earlywireless.com/pdf/pw_xtal...nters_hdbk.pdf

Early cat's whiskers radios would fit the bill; I have some Galena crystals coming in the mail, as well as Germanium diodes which will pick up RF frequencies..

Nice challenge

[Armagdn03]

The problem with traditional impedance changing mechanisms to produce oscillations (like wiskers, spark gaps etc) is the lack of a feedback mechanism. The sparks usually impinge on an LC which creates the frequency, but the rate of spark discharge is highly dependant on local conditions like temp, humidity, etc. To make them reliable a feedback mechanism is required, like a cold cathode tube of sorts, this is a viable solution, and im going to look into it, something like the triggered spark gap that triggers itself.

[Inquorate]

Easy

Put the spark gap in a sealed glass tube; cuts down noise and oxidation of spark electrodes, removes humidity from variables. Then have the lead-in wire wrapped around the glass tube such that once current is flowing, it creates a counter magnetic field that causes the space between electrodes to resist dielectric breakdown.

Like this;

YouTube - c30kv magnetic diode proof of concept

That would self oscillate

[poii]

Sounds like the Corea's PAGD.

http://www.infinite-energy.com/image...plearticle.pdf

p 62

[sebosfato]

Hello Armagedn

" I would be damn impressed if we could come up with a solution which could oscillate a wide range of currents without needing to have 3000v on the input. "

I guess i have the answer but anyway you still need 2 or 3 transistors a diode and a capacitor and 2 transformers one the energy input to the oscillating circuit and the other is a simple and small current transformer. If you wire the current transformer on the base of the first transistor (that drive the transformer) you have a self oscillating circuit you just need to design it so as it can trigger the transistor easily. Than you have a inductor connected in parallel with a capacitor and the wire that connects one of the 2 sides of the parallel connection pass in the middle of the current transformer (small toroid). And the transformer witch have 3 windings 1 primary and 2 secondary with a diode connected between the two secondary windings.

You must find the right polarity for the diode and for the current transformer and you are done.

It will work even at 5v and from this source it can develop up to several Kilovolts and Kilowatts of power consuming few watts of power. It's call tank circuit and is related to the magnetron. It's actually like an AC Battery.

I'm discussing this on my thread: http://www.energeticforum.com/renewa...eyer-true.html

[CosmicFarmer]

I remember reading about a sonic oscillator that would produce mechanical motion through sound, and the sound was produced by a temperature gradient in a tube...

I lost the original page but this detailed "Acoustic Circuits" essay points this out, among other things.

A special and interesting way of exciting a resonator is by means of heat. This requires that heat be added or extracted at the proper phase of the oscillation, and at the proper locations. The singing flame, devised soon after the discovery of hydrogen gas, is illustrated in the diagram, with typical dimensions in mm. The resonator is the open-open tube, which in its fundamental has a velocity node at its centre. A small hydrogen flame is introduced into the bottom of the tube, and when it reaches some position like that shown, the resonator breaks into continuous sound. A tube of these dimensions should sound about an E flat above middle C. Whether the arrangement oscillates or not depends very critically on the length of the supply tube to the flame. As shown, it should be less than a quarter wavelength in hydrogen (about 1 m in this case) at the frequency of oscillation. The flame does not sing with a longer supply tube until its length increases by a wavelength. Other inflammable gases, such as natural gas, can also be used, but it is more difficult to produce oscillation.



When the flame is observed stroboscopically (as was done first by Wheatstone) it is found to vary at the frequency of oscillation, even descending into the supply tube at the pressure minima. Its phase with respect to the oscillation is very important, so that on the average it delivers more heat when the pressure is high at the node, and less when the pressure is low, encouraging the oscillations. A role is also played by the current of heated air in the tube, that continually brings in cool air. The interplay of these conditions makes the most effective position of the flame some distance below the node. It is not an easy phenomenon to analyze, and gave rise to an extended discussion.



A related effect that makes an even better demonstration is Rijke's tube, which I call his "Boomer." It was discovered in 1859, and is quite reliable in operation, not requiring the fiddling associated with singing flames. The gas flame is used to heat a doubled iron gauze placed in the lower part of the tube to bright red heat. When the flame is withdrawn, the tube breaks out into a very loud sound, in this case at around 100 Hz. This remarkable sound continues as long as the gauze is hot, about 10 seconds. In this case the excitation depends sensitively on the upward current of air. The hot gauze is placed where there are both pressure and velocity variations, and the net effect is to add heat in the proper phase. If the hot gauze is placed near the top of the tube, resonance cannot be excited. However, Rijke showed that if this gauze were cold instead, oscillation was again excited. The steady current in this case is downward.

These singing tubes are excellent illustrations of the creation of oscillations by forcing a mechanical oscillator in the proper phase by forces depending on its own oscillation, which is a closed feedback loop of gain greater than unity. Heat is only one agency that may be active in these systems, and it acts rather strongly on gases. I have a saucepan that oscillates on a hot burner, reminiscent of Trevelyan's Rocker, an old demonstration.

Acoustic Circuits

The reason I bring this up is heat could be obtained by focused sun rays through a fresnel lens. I have seen big fresnel's melt nickel and steel.

Also if you prepared several acoustic resonant circuits and arranged them like an organ, small to large, then you could possibly capture broadband noise from city traffic.

[Armagdn03]

@ Poii

Could not get the link to work, I will try searching around for what you suggested.

(update: I got it to work, thanks, reading it over now)

@ sebosfato

Thank you for the suggestions. I want to get completely away from transistors. Think about it like this. The economy fails, all hell raises, suddenly its hard to find a loaf of bread much less a proper transistor! how do you make do with only the simplest of materials, wire, maybe a gap, and other already available materials. This is where I have a problem with IC's and other Semiconductors. If I cannot make it myself, im turned off by the idea!

@ Cosmic Farmer

Thank you for the information. I will look into it further. I really enjoy bridging disciplines as a hoby, especially seemingly non related interdisciplinary things like using temp gradients and sound to create an oscillation, very clever.


I have come up with a pretty wicked idea, and will explain it in a bit here when I get it drawn up properly.

[Armagdn03]

This is my first contender to meet the bill, It is a Self Oscillating Solenoid.


The parts are as follows:

A - single layer tesla style solenoid
B - Primary coil with signal generator attatched
C - Capacitive plates (arranged as a ring to fit around solenoid)
D - Exciter Coil
E - Neon, or other impedance gap
F - Adjustable inductor or capacitor or both to make a phase shifting arrangement.

Here is the operation!

The signal generator B is set to a resonant mode such that solenoid A reaches 1.5 or higher its fundamental frequency. This ensures at least one magnetic peak (about the primary and exciter coil) and two electrical peaks at each end of the solenoid.

The solenoid driven in this mode will have two electrical maxima located on opposite ends of the solenoid, (this is where optical physics plays a large role)

This causes a potential gradient which passes THROUGH the solenoid which is PARALLEL to the magnetic gradient, (NOT OUT OF PHASE 90 Degrees) So that any curent developed through this parallel potential gradient creates a magnetic component with is 90 degrees out of phase with the magnetic potential of the solenoid itself, hence the induced current does not affect the inducing current per lenz law. (this is an interesting side note, not required for operation)

Also, the potential maxima radiate a potential field per the inverse squared law, and in doing so we place capacitive pick up plates within this field (plates marked C)


Each Capacitive plate is connected to one end of an impedance, in this case a neon. A second exciter coil is placed within in series with the neon.

Operation is as follows. Signal generator places solenoid in resonance. Solenoid creates virtual electrical maxima on each end. Per capacitive action, a charge is built upon the capacitive pickup plates which ionizes the neon bulb. This causes a great increase in conductivity, which allows a current (maybe 12v or so) to flow through the neon which could not before. As the solenoid reverses its polarity passing through a zero point, the ionization will cease to occur, shutting the neon off.

Here the neon acts like a triggered spark gap. It is triggered by the electro-optical properties of the solenoid in question.

In order for this scheme to work the exciter coil in series with the neon must be in phase with the signal generator which started the chain reaction. This is the reason for the phase adjuster. At this point, once the solenoid is triggering itself, the signal generator may be removed from the picture.

Now you are left with a single solenoid, a driving potential and a self firing impedance gap.

It is self oscillating, requires lower voltages for operation, (no required 1000v+ initial voltages, 12 - 50v is enough) and it can be adjusted very easily.


P.S. Placing a mechanical push button switch across the neon can serve as a one push pulse which can start the chain reaction, possibly doing away with the signal generator.

[Armagdn03]

Edit,

The frequency felt by the neon by the capacitive plates will be 2x the frquency of oscillation in that each half of the cycle will cause ionization of the gap, so half wave rectification will have to be thrown in to make it impinge at the correct time. Or one could substitute a frequency halving mechanism.

Also, loose coupling is required on the capacitive pickup plates, if it is tight, the energy used in this circuit will dampen the oscillations of the resonating solenoid. Loose coupling is an area of study in and of itself, there are specific geometric ratios which lend to a "one way" effect on transference of energy between coupled elements which can be described in predictable ways.

[CosmicFarmer]

Considering transistors out of the question, how about this 2 stage mechanical oscillator? The input is you. Out put is high volume of water moved.

http://www.energeticforum.com/renewa...scillator.html

As simple as pushing a kid on the swing.

To be honest excluding transistors is a little unfair, unless you want to design something for a post-emp scenario, then I could understand. All these TV's that people can't use due to digital transition are goldmines to us that can take them apart, and contain hundreds of tiny transistors. As long as they still work, I would refine the parts limit to include "anything found".

I believe you can make almost anything out of busted TVs and microwaves.

Just my 2 cents :-)
Keep up with the good thought experiments!

[wings]

multipactor cold cathode

[wings]

multipactor cold cathode

some data on Secondary Electron Coefficient of different materials:

Multipaction