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Author Topic: Dr Ronald Stiffler SEC technology  (Read 278831 times)

Slider2732

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Re: Dr Ronald Stiffler SEC technology
« Reply #585 on: July 16, 2018, 04:54:25 PM »
Nick - it's actually one of my vids that your circuit came from :)
https://www.youtube.com/watch?v=2omcrkrrhoc
It can be confusing though, because Lidmotor came up with the 4 pin crystal circuit and the one I showed was found on a website a few days later. It's by KF50BS, which is presumably his Ham radio name.


All who noticed the funky scope display - The scope appears to be fine, all normal measuring results in normal traces. It only does that weirded out thing on this booster circuit.
The Ground from the scope lead is attached to the Ground of the boost circuit, which itself is connected to the Ground of the AD9850 or 2 pin crystal circuit. Common Grounds being important in these things...at least so i've always thought. Have got no problem with being wrong though if it clears up the output and scope trace !

Or is this a forehead slapping doozy of a thing ?
That because the input voltage for the sig gen or 2 pin crystal circuits is 5V and the input for the booster is 15V, the Grounds should be separate ?

Slider2732

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Re: Dr Ronald Stiffler SEC technology
« Reply #586 on: July 16, 2018, 05:32:37 PM »
Have now connected the scope Ground to the booster Ground and disconnected that link between the AD9850 and the booster.
It's still wonky  ???
Next thing will be to separate all wires as far away from each other as possible. Then shorten to be as small links as possible, then get some coax and try that for connections, then dump the boost circuit into a bath of kerosene and ignite it :)
 
Pics show the output from the AD9850+booster at 15V, at 20V and the 1kHz built-in scope test.
N.B. the scope never actually shows 13.6MHz, it will always flick between 13.5 and 13.7

gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #587 on: July 16, 2018, 09:48:41 PM »
Hi Itsu,

My bad, somehow I missed your post #555 and commented only your post #561 when you were measuring the output to the LED board in the 3 coil setup. So you already gave the answers to my most questions. 

You wrote:
Quote
...
I think we don't need the DC at that middle coil, just the RF AC to excite it.
...
Well, okay but I was pondering why the shorted DC component as a result of rectification may or may not cause loss in the setup? Because the AV plug diodes rectify the RF as they should and if you place a puffer cap across the diodes output, then DC voltage remains and the RF is killed as usual.  Now there is the coil across the diodes output and the DC is surely killed (at least voltage wise) and the RF voltage remains. This is why I mentioned this. 

In the Doc's video his scope showed only a little change in the RF amplitude the probes measured (I do not mean the Math channel) when he removed the 3rd (output) coil + LED board combo,  while in your setup the RF amplitude changes about 5V (from 17Vpp to 12Vpp) when you remove the 3rd coil.  I think this may come from the small differences between your coils especially due to the small difference between the middle and the 3rd  (output) coil.
So probably the 5 Vpp change could be reduced if you replace the input and the output coils with each other: this way, after the change, the two most identical coils would be at the critical places as I think.  Of course we do not know yet whether such 5 Vpp or whatever change at the input of the 3 coil setup may prove to be unwanted or not, I mention this because in the Doc's setup such amplitude change is not seen.

Gyula

gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #588 on: July 16, 2018, 09:52:10 PM »
Hi Erfandl,

Your finding the current draw is reduced with the 3 crystal and the brightness increases is interesting.   :)   Would you mind using a Pi filter in the battery supply rails? I do not really think your Ampermeter is fooled with the 3 crystals operating though.

Just connect the oscillator positive supply wire to the battery via a 1 mH (1000 uH) choke coil.  And connect one-one 10 or 22 or 47 or 100 nF capacitor across the supply rails on both sides of the choke, thus you form a Pi filter.  Such filter greatly reduces any 13.56 MHZ and higher harmonic frequencies going back towards the battery and your Ampermeter which now should be connected between the battery positive and the positive input of the choke, ok?   
Let me repeat: I do not really assume your Ampermeter shows false currents and that is why you see current reduction...  For the time being I cannot give a logical explanation. 

Gyula

gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #589 on: July 16, 2018, 09:58:16 PM »
   Gyula:   I measured the current on my oscillator. Without the crystal it was 22mA, and with the crystal it was 52mA.   This is with the L3 on a load of 10 leds on an AV plug. This is with an 8v input.
   For some reason, now only the 7.2Mhz crystal is doing anything. No light with the other crystals on. 
Wireless near field distance is only about 1 cm away from the L3, as noticed on the led/av plug.
Nick,

Thanks for the current measurement, it shows the transistor (I assume it is still C1815) dissipates about 8 V x 52 mA=416 mW power. This is just the 400 mW limit specified for this transistor in its data sheet at 25 degree Celsius ambient temperature. (Higher ambient temps derates the 400 mW)
So I think your transistors were killed by heat dissipation when run from 12 V supply, current was surely higher than 52 mA, causing much more than 400 mW heat in the transistor, leading to destruction.

A temporary help to reduce heat in the transistor would be to use a 82 or max 100 Ohm resistor in the collector, putting it in series with the 220 uH choke coil you now have there. This way say the 52 mA current would reduce collector voltage by 82 Ohm x 0.052 A = 4.2 V  i.e. the 8 VDC supply would become only 8 - 4.2 = 3.8 VDC for the collector-emitter section, so that transistor dissipation would change to 3.8 x 52 mA = 197 mW only,  less than half of the earlier 416 mW.
Of course, this lower dissipation remains valid for the 12 V operation too but the 82 Ohm may need to be changed a little (perhaps to 76 Ohm), depending on the actual current draw. The goal is to let a 4 or max 5 VDC working collector-emitter voltage for the transistor.

The final (and not temporary) solution would be to use transistors with higher power dissipation ratings like the BD243C type or what Itsu uses. This way normal heat sink could also be used if needed while for the C1815 it is hard to clamp on a cylindrically shaped heat sink but of course it is not impossible.

Make sure that after inserting the 82 Ohm resistor in series with the 220 uH choke, the coupling capacitor should remain connected to the collector directly as before,   for the collector point should remain the oscillator output. 

Gyula

itsu

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Re: Dr Ronald Stiffler SEC technology
« Reply #590 on: July 16, 2018, 10:01:53 PM »

Here the differential measurement across the 2th AV-plug (middle coil) using the oscillator, see screenshot 1
I have offset the both blue and purple traces for better viewing.
The math function (purple - blue) shows a negative result, even when i swap the probes.

The probes have some influence (negative) on the brightness of the leds.

The analoge voltmeter in the supply line goes all the way to max (250mA) so is again influenced by the RF field.




Doing the 1 Ohm csr measurement again using the oscillator posses some problems as the signals are far from
stable (csr in front of the trimmer cap).
Again the result is always negative which way i put the probes and the difference is about the same with
or without the 3th coil/leds strip combo inserted into the 2th coil (between -400 and -650mV).

So i do not really trust this measurement.

Screenshot 2 is with 3th coil/ledstrip inserted,
Screenshot 3 is with 3th coil/ledstrip removed.

Swapping the csr and trimmer cap (trimmer cap in front of the csr) complicates things further as the
oscillator stops when removing the 3th coil/ledstrip (needing new tuning).

Itsu

gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #591 on: July 16, 2018, 10:08:38 PM »
Okay Itsu, many thanks and I will try to digest your findings today but may be able to answer tomorrow evening only, due to some travel daytime, I will see.
Gyula

itsu

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Re: Dr Ronald Stiffler SEC technology
« Reply #592 on: July 16, 2018, 10:35:45 PM »
Hi Itsu,

My bad, somehow I missed your post #555 and commented only your post #561 when you were measuring the output to the LED board in the 3 coil setup. So you already gave the answers to my most questions. 

You wrote: Well, okay but I was pondering why the shorted DC component as a result of rectification may or may not cause loss in the setup? Because the AV plug diodes rectify the RF as they should and if you place a puffer cap across the diodes output, then DC voltage remains and the RF is killed as usual.  Now there is the coil across the diodes output and the DC is surely killed (at least voltage wise) and the RF voltage remains. This is why I mentioned this. 

In the Doc's video his scope showed only a little change in the RF amplitude the probes measured (I do not mean the Math channel) when he removed the 3rd (output) coil + LED board combo,  while in your setup the RF amplitude changes about 5V (from 17Vpp to 12Vpp) when you remove the 3rd coil.  I think this may come from the small differences between your coils especially due to the small difference between the middle and the 3rd  (output) coil.
So probably the 5 Vpp change could be reduced if you replace the input and the output coils with each other: this way, after the change, the two most identical coils would be at the critical places as I think.  Of course we do not know yet whether such 5 Vpp or whatever change at the input of the 3 coil setup may prove to be unwanted or not, I mention this because in the Doc's setup such amplitude change is not seen.

Gyula

Gyula,

i have swapped the output coil (27uH) with the input coil (26.7uH) and left the middle coil (26.7uH).

Using my FG i measure again across the 1 Ohm csr, but still the voltage pp differs about 5V (17V v 12V)
leaving a steady 40mV difference with or without the 3th coil/leds.


The problem i notice now however is that the Vpp on the csr input (from the FG) is lower then on the
csr output, see screenshot.

Blue is on input csr (next to the red lead FG), purple is on output csr.
Math function is blue - purple giving a negative value.

I believe that was also the case (more Vpp on output) on the post #555 screenshot but am not sure.

Need to do some more tests tomorrow.


Itsu

itsu

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Re: Dr Ronald Stiffler SEC technology
« Reply #593 on: July 16, 2018, 10:36:39 PM »
Okay Itsu, many thanks and I will try to digest your findings today but may be able to answer tomorrow evening only, due to some travel daytime, I will see.
Gyula
No problem, take your time,  doing the same overhere.
Itsu

gyulasun

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Re: Dr Ronald Stiffler SEC technology
« Reply #594 on: July 16, 2018, 11:07:55 PM »

Hi Slider,

Let me suggest this: first adjust a some kHz or some 10 kHz output frequency for the AD9850 board and check its waveform, it should not be wonky. Your scope nicely shows the 1 kHz built-in test signal, though I am surprised it has 30 Vpp amplitude ? (It can be correct of course I do not know your scope and I got used to 5 Vpp built-in test signals.)
If the lower frequencies are nice-looking, taken directly across the output from the AD9850 board, then drive the boost circuit with such low frequency signal and see then its output how it operates at low frequencies too. Of course you need to reduce the output from the generator to as low as some 10 mVpp maximum, not to overdrive the booster.
If that also seems ok, then increase the output frequency and sweep or simply step through up to the hundred kHz and then to the some MHz range.

I just watched your video entitled "AD9850 signal generator - arrived, built, tested" where you went up to 29.999 MHz.
Would like to ask whether the output impedance for the AD9850 board is specified as ?  Is it a low impedance like 50 Ohm or some hundred Ohm?  I ask this because as you surely know, normally such generators should be terminated by a non inductive resistance that equals to their own output impedance, this way the change you see as a gradual amplitude decrease across the output becomes less than in the unterminated case. OF course I know that for the Doc's tests the generator is used as unterminated but if a booster is used then a decent termination across the generator output is helpful for a nicer output waveform.
Be careful with such termination directly across the generator output because if there is a DC level at the output too, then it should not be terminated by a low value resistor directly but only via a series coupling capacitor. 

"then dump the boost circuit into a bath of kerosene and ignite it :) "   I think you can wait with this...  ;D

Gyula
Edit: if the waveforms remain 'wonky' via the booster only (but good from the gen output), then try to use a 9 or 12 V battery as the power supply for the booster to make it totally ground independent and see the waveforms then. 

TinselKoala

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Re: Dr Ronald Stiffler SEC technology
« Reply #595 on: July 17, 2018, 12:41:34 AM »
@gyula, slider:
Yes, the Rigol scope puts out a 3v (approx) max p-p voltage from the probe compensator output. The probe 1x-10x switch or the channel attenuation setting is not correct in Slider's scopeshot above.



Slider2732

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Re: Dr Ronald Stiffler SEC technology
« Reply #596 on: July 17, 2018, 08:04:57 AM »
Gyula - Many thanks for the tips.
Will try the 9V battery and look into the exact terminations. All I usually see is 'into a 50ohm load' and have no real idea how the load can be exactly terminated in that way. It's all new, apologies for that.

TK - OMG, as they say, yes of course. The scope is usually over at the usual bench, but I tend to move it to the far cleaner table for vids etc. The usual scope lead was over at the other bench, so I grabbed another and...didn't check whether it was on 1x or 10x
:)

All - Found something of possible interest, which I would have thought would have reared as a fault or feature, but haven't seen it mentioned. The Dr. Stiffler type L3, with 2x AV plugs, an LED and length of floral wire can be used as a tester for mains wiring continuity.
The circuit is shown in the video and there is a positive reaction with wood, believe it or not. Maybe it's because of the humidity here in Oklahoma, but the thing has some very strange properties.

https://www.youtube.com/watch?v=c4hCiUUcZ18

shylo

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Re: Dr Ronald Stiffler SEC technology
« Reply #597 on: July 17, 2018, 10:34:51 AM »
Hi Slider,
That is interesting, how is the floral wire connected? I assume the circuit you showed is showing the 75 turns on tube connected to the diodesor is that the floral wire and you don't show the 75 turn coil?Thanks artv

erfandl

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Re: Dr Ronald Stiffler SEC technology
« Reply #598 on: July 17, 2018, 10:47:11 AM »
Hi Erfandl,

Your finding the current draw is reduced with the 3 crystal and the brightness increases is interesting.   :)   Would you mind using a Pi filter in the battery supply rails? I do not really think your Ampermeter is fooled with the 3 crystals operating though.

Just connect the oscillator positive supply wire to the battery via a 1 mH (1000 uH) choke coil.  And connect one-one 10 or 22 or 47 or 100 nF capacitor across the supply rails on both sides of the choke, thus you form a Pi filter.  Such filter greatly reduces any 13.56 MHZ and higher harmonic frequencies going back towards the battery and your Ampermeter which now should be connected between the battery positive and the positive input of the choke, ok?   
Let me repeat: I do not really assume your Ampermeter shows false currents and that is why you see current reduction...  For the time being I cannot give a logical explanation. 

Gyula
Hi gyula. thanks for reply. can you draw Pi filter circuit ? I cant understand how to build the Pi filter. thanks

Slider2732

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Re: Dr Ronald Stiffler SEC technology
« Reply #599 on: July 17, 2018, 01:55:57 PM »
Shylo - The floral wire connects to the negative lead of the LED.
The other end of it is buried somewhere in the spool it is on.
In practice, you can simply hold the circuit by that point and it will still partially work around mains wiring. The floral wire is like a big clip lead.