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Author Topic: Dr Ronald Stiffler SEC technology  (Read 277044 times)

mikrovolt

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Re: Dr Ronald Stiffler SEC technology
« Reply #420 on: July 01, 2018, 05:51:48 AM »
Itsu, Gu and all, great job looking at SEC 6.5 Mhz 6/24/11 Stiffler youtube video notice the in between harmonics
and a redistribution in amplitude.  Possibly a doubler and diode action ?

I took a few screen captures of Dr. Stiffler using spectrum analyzer and I am listing the following data.
not exact but fairly close as tests can very slightly. atten 10 db, center 25 Mhz, span 50 Mhz, 5 Mhz/div
(6.5, -17db) (13.13,-60db) (19.75,-45db) (26.25,-38db) (32.75, -45db) (39.38,-52db) (45.88,--50db)
another frequency series taken from my notes: antenna on spec analyzer
(6.8 ) (13.6 ) (20.4 ) (27.2 ) (34 ) (40.79) (47.6)

your harmonics agree with standard
http://mustcalculate.com/electronics/harmonics.php?f=13.494599M

erfandl

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Re: Dr Ronald Stiffler SEC technology
« Reply #421 on: July 01, 2018, 08:46:18 AM »
testing 13.56 mhz crystal circuit with RFID 13.56 MHZ external antenna


itsu

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Re: Dr Ronald Stiffler SEC technology
« Reply #422 on: July 01, 2018, 11:46:02 AM »

Gyula,

you are a wizzard with transistors, thats for sure, and its good to show us (refresh) on the workings of one
as i better understand the processe that makes the oscillator work, hopefully.

I will make the BF869 to oscillate eventually, its like what TK said:
"Amplifiers that oscillate, and oscillators that amplify".

 


Nick,

even with known components its hard enough to get this (tank circuit) oscillator to work, so without
knowing you use the correct valued components its probably impossible.
Try more different values for the cap and see if it starts oscillating on its own, you must be almost there.

I have asked my local post office to start an investigation on the send parts, so waiting for their respons.

Itsu 

Ed morbus

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Re: Dr Ronald Stiffler SEC technology
« Reply #423 on: July 01, 2018, 03:17:42 PM »
13.5 MHz Crystal can you find in the old wireless microsoft mouse

NickZ

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Re: Dr Ronald Stiffler SEC technology
« Reply #424 on: July 01, 2018, 03:55:06 PM »
   Ed:   Thanks for the tip. I just opened up one of my old wireless mouse, and sure enough, there's the 13.5MHz crystal inside.   I'll be pulling it out ASAP.    Thanks again. Great tip.

   EDIT: After opening up and removing the mouse circuit board, I found not one, but two 13.5MHz crystals. My lucky day... 
Now I have the right component for the job. And I had it all along. Sweet!!!  There is also a small black inductor, with a black dot on top. What value might that be?  1000uH, perhaps.
                                                                                                                                 

Ed morbus

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Re: Dr Ronald Stiffler SEC technology
« Reply #425 on: July 01, 2018, 07:00:26 PM »
Your welcom Nick

Have some one information for the coil or how to

itsu

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Re: Dr Ronald Stiffler SEC technology
« Reply #426 on: July 01, 2018, 07:29:10 PM »

Got the BF869 as oscillator running.
I removed the 5K trimmer pot and replaced the 100K fixed base resistor by a 50K trimmer pot and added a 47pF cap across collector/emitter.
The 50K pot was set to 18.5K when the below screenshot was taken.

So we have 12.5V from the battery and 18.5K base resistor meaning we have 0.67mA running in the base
Times 50 as hFE so we have 33.7mA quiescent collector current

12,5V / 18.5K = 0.67mA   x 50 = 33.7mA

But the signals are nowhere near what i got with the BC337 and i see an elevated collector signal (blue trace, yellow is output signal behind the 100nF cap).

Itsu

Lidmotor

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Re: Dr Ronald Stiffler SEC technology
« Reply #427 on: July 01, 2018, 07:50:07 PM »
All---Another crystal circuit replication popped up on YouTube done by channel called 'JB-N107Lab'.
   There is no dialogue but he shows that he is getting the job done.  He is using a very interesting compound AV plug (Stiffler Loop) as the load.
  He is also finding that 13MHz is not critical and has done a series of videos with the circuit.

Here is one of them:
https://www.youtube.com/watch?v=nqxBg8-pzPA

erfandl----  I ordered some of those little RFID 13.56MHz antennas but they have not arrived yet.  I was glad to see that you got yours to work on the circuit.

Ed----The coils (L3 I guess we are calling it) people are using are based on Dr. Stiffler's SEC 18 L3 coil.  If you look back a few pages you will find more discussion on that.

Mikrovolt---Thanks for the info on the frequencies and harmonics.  That really helped me understand what I am seeing.  I have been doing pulse motor testing using a single wire feed off my signal generator and it has been confusing.  I got the motor to run on some strange frequencies and it might be a harmonics situation.

Nick -- Keep at it.  As I recall you live in Costa Rica and I can imagine how hard it is to get parts there.  All the stores near me that sold electronics parts have vanished and I have to order parts online or innovate circuits with stuff I have on hand.  I feel your pain. 

---Lidmotor

Ed morbus

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Re: Dr Ronald Stiffler SEC technology
« Reply #428 on: July 01, 2018, 08:43:17 PM »
Thanks Lidmotor i want more information for L1

gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #429 on: July 01, 2018, 09:06:03 PM »
Hi Itsu,

Okay, good! I assume you checked the 33-34 mA quiescent collector current when the crystal is removed? It would confirm the assumption of hFE being really around 50 (I took it from data sheet, it said as minimum 50).

The elevated collector waveform indicates that the AC impedance (i.e. that of the 4 turn tap) across which the hFE can amplify is low. In fact, it is the hFE which is low versus that of a BC337-40 but now you surely have less than maybe 100?.

Ideally the AC collector voltage should swing between zero and about twice the supply voltage. (I have not mentioned this yet.) To increase AC impedance for the collector and have higher gain as an amplifier, you would need to make taps at 5 and 6 and maybe at 7 turns and see the collector waveform and also the full AC peak to peak across the trimmer capacitor.  When the tap is moved higher, the resonant voltage step up decreases but maybe the gain by the higher AC impedance could compensate for it in a certain degree.

The probe self capacitance is added via the 100 nF to the 47 pF cap you placed across the collector-emitter, of course. I wonder what is the tank trimmer cap capacitance now? Can you easily tune it to maximum tank voltage?  (The probe capacitance is also across the tap, not only across the collector-emitter.)
Thanks,  Gyula

itsu

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Re: Dr Ronald Stiffler SEC technology
« Reply #430 on: July 01, 2018, 10:39:11 PM »

Gyula,

i just wanted to make this BF869 to oscillate with minimum changes in the circuit and now it did i will
leave it at that and continue with the BC337 which stays cool at around 100Vpp output.

I redid my L3 coil and have it resonate at 13.5MHz with the leds connected using my FG as drive.

When i use the BC337 oscillator set at 100Vpp output to drive it then the leds come on faintly, so
more tuning needs to be done.

When i connect a virtual ground (cliplead to the 2 1N4148 diodes center junction), then the leds really
take of, so i will use that virtual ground and tune to the max (5K trimmer pot inserted again as with
direct connect to the 12.5V battery, the oscillator flips to 3th harmonics (40MHz)).

Itsu


gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #431 on: July 01, 2018, 11:49:11 PM »
Hi Itsu,

Thanks and I understand,  okay.

The tuning for L3 in advance by the FG differs from what will be needed from the oscillator output, unfortunately, mainly because the FG output is purely resistive (no reactance). And first, I think, when L3 is connected to the oscillator and the LEDs are also attached to L3, it is the C_var trimmer cap which would need retuning a little first and then L3,  and then the trimmer cap again and so forth. They can mutually detune each other and this should be corrected in alternative steps, the indicator for tuning can be the LED brightness.

It is strange that the oscillator flips to its 3rd harmonic: how can the AC impedance of the collector tank be enough at 40 MHz when it is tuned to 13.5 I wonder.  Can you increase the capacitor value between the base-emitter up to say 50, 70 or even 100 pF? Maybe that will kill amplification at 40 MHz at the transistor input.
Gyula

Slider2732

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Re: Dr Ronald Stiffler SEC technology
« Reply #432 on: July 02, 2018, 07:45:44 PM »
Could the 3rd harmonic situation be related to the early experiments, where an LED in series with the +V input to the crystal lowered it by 3x ?
Example would be a 12MHz crystal that reported as running at 4MHz.
Something about the voltage stability maybe ?


Following a tip by iQuest, i've just got the FFT function going on my Rigol 1054Z.
The idea, is to make use of it with these and related projects.
Dr. Stiffler used to show the FFT output of his experiments and looking at the harmonics might be a clue when changes are made.
Pic attached of where am up to with setting it up...here shown measuring a possible exciter, based on 2 chokes. The FFT display itself is tiny and pressing the Hz/Div only seems to change the Offset, as indeed does the actual Offset button below it.
The scope was 'jailbroken' finally, have never done that and it now reports as a DS1104Z.

Itsu - I know you have been using your FFT and am wondering if your harmonics flip at a specific point of circuit tuning.





gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #433 on: July 02, 2018, 08:51:02 PM »
Hi Slider,

The example you mention: was it a 2 pin crystal or was it a 4 pin crystal oscillator?
I think the two cases are different: the 4 pin oscillators usually need 5V supply voltage +/-0.25V and a LED in series with them may reduce the voltage below the specified range, thus the internal RC coupled amplifier circuit may provide a favorable condition for oscillations at an odd numbered subharmonic of the built-in crystal. (This also depends on the cut of the crystal.)
And inside the casing of the 4 pin oscillator there is no tuned LC circuit while in Itsu's circuit case a single transistor works for high Q toroidal tank which should give additional selectivity for 13.5 MHz, this one thing in itself would show why the 40 MHz frequency is strange to appear. 

Gyula

itsu

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Re: Dr Ronald Stiffler SEC technology
« Reply #434 on: July 02, 2018, 10:03:15 PM »

Gyula,   Slider,

i made a video about my present setup showing the flipping into 3th Harmonics operations etc.
Also the spectrum (0 - 500MHz range) is shown on my Spectrum Analyzer both at 13.56MHz as with 40MHz operation,
see also the screenshots with harmonics table at both situations (the 104MHz at 2th screenshot is a local FM station).

I keep the input voltage low via the 5K trimmer pot to protect my transistor by limiting the collector signal at twice the input voltage, so roughly at about 24Vpp.
If i increase the input voltage it seems the signals get stronger and better (sine wave like), but my transistor won't stand it for long (46Vpp at the collector).

At the end i inserted a 47pF cap across base/emitter, but this does not prevent the oscillator to flip into 3th harmonics operation, even a 100pF cap seems to have no influence.

Video here:  https://www.youtube.com/watch?v=-MJZNHmHovc&feature=youtu.be

Itsu