The Jeffree Cell

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Re: The Jeffree Cell

Postby Harry Dalek » Tue Mar 05, 2019 3:49 pm

On the newer Ultrasonic piezo Transducer idea i found they can be got up to 3MHZ
https://applevista.en.alibaba.com/produ ... _28mm.html
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Great information in old magazines,every little be helps
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From the magazine above..interesting to see the size of a 1926 crystal and its holder types.
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Jeffree Cell

Postby Klaas Robers » Tue Mar 05, 2019 7:00 pm

If you look at the holders, in most of them the crystal is mechanically held flat. That implies that the crystal cannot vibrate in thickness or bending mode. That is understandable, because in that mode the crystal is giving sound, that is it emits power to the air. That decreases the resonance sharpness, which is the only task of a crystal for frequency control of a transmitter or receiver. So crystals made for that aim will not give sound into a liquid or a solid (glass).

So the crystals that you opened are not usefull for making ultrasonic sound in water / oil. Then the ceramic transducer is a better thing. Those transducers are used as under water microphones for sonar. They emit sound and receive it again.
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Re: The Jeffree Cell

Postby Harry Dalek » Wed Mar 06, 2019 9:04 pm

Klaas Robers wrote:If you look at the holders, in most of them the crystal is mechanically held flat. That implies that the crystal cannot vibrate in thickness or bending mode. That is understandable, because in that mode the crystal is giving sound, that is it emits power to the air. That decreases the resonance sharpness, which is the only task of a crystal for frequency control of a transmitter or receiver. So crystals made for that aim will not give sound into a liquid or a solid (glass).

So the crystals that you opened are not usefull for making ultrasonic sound in water / oil. Then the ceramic transducer is a better thing. Those transducers are used as under water microphones for sonar. They emit sound and receive it again.


Yes Klaas you picked up some thing i didn't notice about vintage crystals they are held in place flat some thing different really to the modern crystals which can vibrate held either end by thin rods ,perhaps the size and the thickness is larger for an old crystal .....Still the jeffree cell was made with some thing like this with an x cut crystal ....how they did it is amazing ....I will have a look at the world war 2 crystals when they come and take notice of the construction of the holder contacts ...i think the crystal would be either a y or x cut type .
I am thinking the same on the newer ceramic idea that its is an easier and and more efficient way of doing it ...a Lot less voltage needed as well for the oscillator ...frequency its a bit lower ,i have seen they will make to order frequency wise and mentioned and one selling site 5 MHZ or what ever but that i am sure costs ! i will experiment with the 1.7 mhz and see nice to make cell and get away from liquid every where and do some light experiments .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Jeffree Cell

Postby Klaas Robers » Fri Mar 08, 2019 1:13 am

The modern high frequency crystals vibrate in a "shift-mode". That is, if you lay the crystal flat on the table, that the top plane and the bottom plane move left-right-left with respect to each other. This gives only visible and feelable movement at the very thin left and right edges. The larger old crystals have much lower resonance frequencies, because the frequency is directly coupled to the dimensions of the crystal.

At resonance there is an accoustic movement / standing wave in the crystal. In most cases the length / thickness is 1/2 wavelength of the accoustic wave in the crystal. Accoustic waves travel in crystal, but also in glass, with a speed of about 5 km/sec. So a crystal of 10 MHz carries a accoustic wave with a wave length of 10 000 (m/sec)/ 10 000 000 (MHz) = 1/1000 meter. You will see that the crystal has a thichness of 1/2 mm, i.e. the size of a half wavelenght. If you have a micrometer, measure the thickness of your 4,4 MHz crystal.! Then you can calculate the exact speed of sound in the quartz.

Low frequency crystals are large. A 100 kHz crystal has (in this case) a length of 5 cm. Yes, it is as simple as that.
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Re: The Jeffree Cell

Postby Harry Dalek » Fri Mar 08, 2019 1:09 pm

Klaas Robers wrote:The modern high frequency crystals vibrate in a "shift-mode". That is, if you lay the crystal flat on the table, that the top plane and the bottom plane move left-right-left with respect to each other. This gives only visible and feelable movement at the very thin left and right edges. The larger old crystals have much lower resonance frequencies, because the frequency is directly coupled to the dimensions of the crystal.


Hi Klaas thanks for the Informative reply that does make sense from what i have noticed very much so on the 2 mhz crystal where the liquid tends to gravitate to one of the edges .
At resonance there is an accoustic movement / standing wave in the crystal. In most cases the length / thickness is 1/2 wavelength of the accoustic wave in the crystal. Accoustic waves travel in crystal, but also in glass, with a speed of about 5 km/sec. So a crystal of 10 MHz carries a accoustic wave with a wave length of 10 000 (m/sec)/ 10 000 000 (MHz) = 1/1000 meter. You will see that the crystal has a thichness of 1/2 mm, i.e. the size of a half wavelenght. If you have a micrometer, measure the thickness of your 4.4 MHz crystal.! Then you can calculate the exact speed of sound in the quartz.


So there is a time delay via the crystal and also a speed delay depending on what liquid is used (density) if we are talking of it in the form of a jeffree cell very much a delay line happening , i don't have any thing to test the thickness of a crystal no way on a newer one , the larger ones coming perhaps .

Low frequency crystals are large. A 100 kHz crystal has (in this case) a length of 5 cm. Yes, it is as simple as that.


I think crystals of the same frequency a large older one and a newer small case type thickness would follow the large would still be thicker ..higher the frequency thinner the crystal the lower thicker it would be `,i am interested to see how thick the 8 mhz one's coming are ..will show them when they turn up .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Jeffree Cell

Postby Klaas Robers » Fri Mar 08, 2019 11:07 pm

If the sound wave runs in the thickness of the crystal, the size doesn't matter. A 4 MHz crystal had always the same thickness, if the speed of sound is the same in both crystals. For quartz that will be the case I believe.

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I made a small drawing if the vibrating crystal. As far as I remember, this is the AT-cut. The red and the blue lines indicate both shapes. The arrows show the directions of movement of the upper and the lower surface. You might see that all the action is in the horizontal direction and there is hardly any activity in the vertical direction.

This implies too that if you make the crystal wider, nothing changes. Then the thickness is the "mean" thickness. Now that we can make crystals more precize, we can also make them smaller.
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Re: The Jeffree Cell

Postby Harry Dalek » Sat Mar 09, 2019 9:40 pm

Klaas Robers wrote:If the sound wave runs in the thickness of the crystal, the size doesn't matter. A 4 MHz crystal had always the same thickness, if the speed of sound is the same in both crystals. For quartz that will be the case I believe.


On the small crystals there is a thickness difference i can just notice but i can see very much so on the size and the thin plate electrical connection size is large on low frequency crystals and small on high frequency crystals .
Old crystals the electrical connections are over the full area of the crystal i wonder why now there's a difference


I made a small drawing if the vibrating crystal. As far as I remember, this is the AT-cut. The red and the blue lines indicate both shapes. The arrows show the directions of movement of the upper and the lower surface. You might see that all the action is in the horizontal direction and there is hardly any activity in the vertical direction.


On the crystals cut ....your drawing of the direction of vibration on a At cut reminds me here of the 2 Mhz crystal in video instead of directing the oscillations to a circle point center of the crystal as i see in my past experiments (they must be an x cut )it forces the liquid to the outer edges so another cut AT cut sounds right from your description
water used here



This implies too that if you make the crystal wider, nothing changes. Then the thickness is the "mean" thickness. Now that we can make crystals more precize, we can also make them smaller.


So you would think a crystal of today and a crystal of the past the size is not that important but thickness is of cause for frequency ...at first i thought that the thickness of say a 4 mhz one would have to be the same as one in the past but just larger ...i can only speculate here and look at old pictures till i get my hands on one.
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Jeffree Cell

Postby Harry Dalek » Sat Mar 09, 2019 9:54 pm

Now i don't know what to make of this on Quartz crystals ! new to me ,i would of thought we would have flying saucers by now if this were true ... :shock:
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Re: The Jeffree Cell

Postby Andrew Davie » Sun Mar 10, 2019 2:41 pm

Harry Dalek wrote:Now i don't know what to make of this on Quartz crystals ! new to me ,i would of thought we would have flying saucers by now if this were true ... :shock:


You're all setup to perform that experiment, aren't you? A decent pair of digital scales would be cheap.
I'd be very curious to see if you can nullify gravity, Harry!
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Re: The Jeffree Cell

Postby Harry Dalek » Sun Mar 10, 2019 6:39 pm

Andrew Davie wrote:
You're all setup to perform that experiment, aren't you? A decent pair of digital scales would be cheap.
I'd be very curious to see if you can nullify gravity, Harry!


Narrr not this one Andrew hard enough to get the buggers to vibrate

Not only does it nullify Gravity to the point where its anti gravity really and it increase's in mass from voltage or at least from its original size ...now this is interesting more how it got in the magazine ....i take it this bit of science fake never went any where a good thing too just in time for Hitler to use it in the next few years ...or may be those Nazi ufos were real with high voltage Quartz drives :wink:
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Jeffree Cell

Postby Harry Dalek » Sun Mar 10, 2019 8:10 pm

The original idea here is just seeing how far this can go with the Quartz but i do think it would be much easier with PZT piezoelectric ceramic to make a Jeffree cell ...
The PZT piezoelectric ceramic is very interesting i have an idea or 2 i want to try out with them
Back on the Quartz and the Quartz Jeffree cell oscillator i noticed if you tap the crystal you can Am modulate the carrier the effect is more to the center of the crystal ,i think if you made a paper cone you might be able to modulate your voice or sound sort of turning it into a mic just a little silly experiment ..transmitter on the SW band ...it has an AM modulation via the second Triode any way for what it was made for but shows mechanical effect on the crystal does also work in reverse as in response to applied mechanical stress.
Any one else that makes the Triode Harley oscillator modulator make sure all Caps are High voltage , I had trouble of late with a Trimmer cap to the oscillator control grid i replace the fixed cap 20pf i think it was with a variable one the dielectric failed on the trimmer after a while and causing the oscillator to play up ..... i used a air gap version you might noticed in one of the videos posted a day back or so back to working fine again .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Jeffree Cell

Postby Harry Dalek » Mon Mar 18, 2019 3:30 pm

Have been waiting for my ebay goodies to turn up and the first lot has ,which are now mine the world war 2 8 Mhz Quartz crystals ...boy the cases are big hate to think of the size of the gear they came out of no attempt at Miniaturisation i bet .
I am interested to see the crystal its self ,looking at the bakelite plastic the holes where i think the case is screwed together has what looks like a dry putty filling the holes ...I will show the crystal once i get one open but out of interest i would like to test them as is if they still work after all these years .
I need to convert the Valve Hartley oscillator to a higher frequency top it will do with the current coil is 6 mhz,so not useful for tests yet with these .
Shown below are mainly the 2 1945 crystals but the 3rd is 1944.
I have also looked into a a soild state version which at first i was just thinking of trying just for the ceramic ultrasonic disks but might be fine for the Quartz idea as well i use a LTC1799 as the oscillator as you can use it over a wide frequency range ,i wanted it for the 1.7 Mhz version coming and later on for a 3mhz one any way i feed that 1.7mhz square wave to a Bu2525AF power NPN and a inductor on the collector it is a .03mH showing 1.8ohm....the LTC1799 is 5volts and at the moment the transistor has a 12 volt supply and waveform increase's with voltage here i could over 1000 v if i wanted not that it would be needed or wise to do so only need 30 volts most for the ceramic disks and Quartz a few hundred ....get a very clean large sinewave at the wanted frequency ...any a other frequency i would more than likely have have to change the inductor .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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