Overunity Device using Magnets in the 1920's ?

[hansvonlieven]

G?day all.

Today I want to put a subject into the arena that to my knowledge has never been discussed here, though it should be. The device I am talking about is from the early days of radio and may well have exhibited overunity.

There is little detailed information of it on the net (one wonders why), so at the risk of boring some of you that are familiar with the history and technology I will start at the beginning.

I will leave aside the very early forms of wireless transmission via spark gap transmitters and coherer circuits as receivers, for they have nothing to do with the subject under discussion other than being a historical precedent.

The real revolution came about as the result of the researches of a man with the unlikely name of Greenleaf Whittier Pickard.

Greenleaf Whittier Pickard (born Feb. 14, 1877, in Portland, Maine) discovered that certain crystals, when touched by a fine wire (called a cat?s whisker) in certain spots, were capable of detecting RF waves and converting the signal into audible form. Thus he discovered semiconductors. Pickard patented his device in 1906.

This led to the development of the crystal receiver, or crystal radio as it was later known, which made its general appearance in around 1920 when it became a fad to build these receivers amongst radio amateurs.

The first sets were almost unbelievably simple. Here is a picture of the most basic form. You can build one of these today, it will still work.

As you can see it consists of an antenna, a tuneable coil a crystal detector (commonly a Galena crystal touched by a very fine silver wire) and a set of high impedance headphones. Antennas were usually between 30 and 100 feet long and about 10 feet or more off the ground. A good earth and a good antenna are crucial. There was no power other than what the antenna could drag in, which was typically in the Micro-Watt to small Milli-Watt range.

The next real trick was to convert these very small currents into a pressure wave to make them audible. Luckily the device that could accomplish this was already invented. Telephones were then in existence and the telephone earpiece made a good starting point.

So how did this work?

The feeble current was fed into the coil of an electromagnet A. This in turn magnetised the soft iron core B in harmony with the strength of the signal, attracting the steel membrane C accordingly and creating a compression and decompression zone adjacent to the membrane, allowing these pulses to be perceived by the human ear.

For convenience and to cut out extraneous noise two these devices were employed in parallel and clamped to the ears of the listener. A contemporary headset is pictured in Fig.2. Although the device pictured is from around 1930, they were available in almost unchanged form from around 1910 until the late 1950?s.

Coil impedance was generally between 1000 to 2000 Ohm, although coils with up to 4000 Ohm were in use at some time or other. This is very high by today?s standards where 8 or 16 Ohm are common. The coils were wound with incredibly thin wire, thinner than a human hair, often silk insulated, which was quite an engineering feat in itself at the time.

OK, so much for background history and technology.

Headphones, at the best of times, are a pain in the butt. The headsets of early times were a hundred times worse. The metal membrane kills virtually all bass and has a tinny, grating sound which is hard on the nerves for extended periods. On top of this searching for a station would, in between signals, pick up static that screeched in your ears and send you almost deaf. Not a really good experience I can tell you. Apart from this, the things are uncomfortable and do not allow sharing of the broadcast, as two headsets on a single receiver are too much for the signal to drive.

The race to make it audible to more than one person was on. Thus the loudspeaker was born. A number of avenues were explored, including the use of a gas flame but since they are only of peripheral interest I will leave them aside.

The breakthrough came when some bright spark came up with a novel idea.

History appears to be strangely silent on the events leading up to this monumental discovery, in fact the whole thing appears to have disappeared from the text books, except in nondescript allusions. Again, one wonders why.

Instead of using an electromagnet to energise the membrane by direct influence he did the following:

He placed a soft iron reed B mounted on a support H via a piece of spring steel G, put it inside the coil A instead of a traditionally rigid core and found that the reed vibrated with the magnetic fluctuations.

Thist would not have given him much sound, but he went further.

Next he placed a permanent magnet around the device in such a fashion that the iron reed moved between the jaws of a permanent horseshoe magnet. To make the effect more pronounced he added pole shoes to the magnet to concentrate the field in the vicinity of the iron reed. He then added a connecting rod and a paper membrane to the device.

Like this:

The effect was stunning. Suddenly the signal was amplified many times, to the point where it could drive a 7 inch paper cone and make the signal audible way beyond what a headset could produce, without additional input of energy. WOW! Hello There! (I will come back to this later.)

The trouble with this device was its poor performance acoustically. If the signal got too strong the soft iron reed hit the permanent magnet and got stuck there for an instant before the signal dropped to a point where it let loose again. This meant that the device could only be run at low volume.

I don?t know who invented this device, in spite of all by best efforts I have not been able to find out. There MUST have been a patent, if it still exists, as it should, I have been unable to find it. Make of that what you will.

Patents aside, this is not where development stopped.

The next development in this area was what German literature calls the Freischwinger. English literature is strangely silent on the matter.

Again, I have trouble locating who was responsible for this. One would have thought that in relation to  a device like this, which was used by countless manufacturers from around 1925 to 1945 at least, and is still being used in some devices today where quality does not matter as much as very low current consumption, the relevant patent should be readily locatable, but no such luck.

Anyway, here it is:

So, what are we looking at here?

Someone, perhaps the original inventor, took the system one step further, Instead of placing the electromagnet and its sphere of influence inside the horseshoe magnet he put it outside. Though still within the field of influence of the horseshoe magnet, the soft iron reed was now free to move outside the limits of the pole shoes. (Thus the German term Freischwinger, which means ?free to swing?) This allowed for much bigger amplitude. The result was much increased volume. In fact optimum volume since the device has never been improved upon.

Leaving its poor acoustic performance aside, I think we are looking here at a genuine amplification phenomenon. Energy is entering from somewhere. Keely talks about this, so do a lot of others. Rather than following a lot of dead avenues such as the Tasnierius device, the Perendev or Minato wheels, which have not produced anything of value, I suggest you look at this phenomenon. At least it works. Is it overunity? I don?t know for sure, but I would say it is likely.

Just to show how real this is have a look at the following photos:

This is a photo of the real thing. Notice the horseshoe magnet, the coil, the soft iron reed and the connecting rod that goes through the wall energising the membrane.

Here is the whole device, the Fl?chenlautsprecher Nora L 10 - Jahrgang 1926

(sold and manufactured in 1926 in Germany) The German Volksempfaenger produced before and during the war had a similar loudspeaker.



Just think about it!

For better or worse,

Hans von Lieven

[fleebell]

photos?  where?

[hansvonlieven]

LOL fleebell,

you were too quick for me, Still uploading 

Hans

[fleebell]

 I don't know about all the rest but that top photo is interesting. I used to have a book many years ago that was printed around the turn of the century with almost the same drawing.  It had a 1 meg pot instead of the coil and and another ground rod instead of the antenna . We used to use the little high-z earphones you could get from radio shack with it. (those strange looking pink ones they sold)   Some of us (teenagers at the time)  tried it out and found out you could tune in the local telephone conversations in the neighborhood.  I guess it was picking up some kind of electromagnetic ground waves.  I never could figure out how a 1 meg pot could tune it though but it did.  Learned  a lot of interesting things about the neighbors though 

The rest looks like it would be easy enough to try out and see what happens.
Lee

[helmut]

@Hans
Thanks for the insight.Very interesting lesson.

helmut