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OverUnity Research > Benches > Itsu (Moderator: Itsu) > Tiger's Blocking Generator replication
2024-11-26, 10:29:38
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Author Topic: Tiger's Blocking Generator replication  (Read 14771 times)
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Re: Tiger's Blocking Generator replication « Reply #25 on: 2021-09-25, 01:24:16 »

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Quote from: Itsu on 2021-09-17, 21:53:06
The fist 20 seconds show a similar signal i think as shown by Tiger in his video.
Then the voltage suddenly drops from 12V to 2v or so and the pulse train becomes differently for some 6 minutes.

Video here:  https://youtu.be/cFdOazjelQs
It looks like in Tiger's video, the system never switches to the 2V operating mode but instead something weird happens at 3:10.

If I were to guess what is going on, I'd venture that the ferrite responds in an unusual manner when the circuit attempts to enter the 2V operating mode ...and reenergizes the system, effectively keeping it permanently above the border of the 2V operating mode. 
This is probably ferrite specific behavior (including its remanent magnetization) which is also dependent on internal and external/ambient magnetic flux densities (or their histories) that the ferrite was subjected to.

One other clue about matching his operating mode to yours more precisely is his >2Hz pulse repetition frequency (PRF) versus yours at 1.8Hz. 
I suggest that you measure the time between the pulses that his wireless mic picks up at 1:35 to obtain a more precise PRF and attempt to match yours to his by varying the capacitances, windings, air gap and the elephant in the room.
« Last Edit: 2021-09-25, 11:20:08 by verpies »
   
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Re: Tiger's Blocking Generator replication « Reply #26 on: 2021-09-25, 09:38:26 »

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Yes, i can see the decrease in amplitude in my setup, but this "turnover point" where it bounces back to an increase is missing here.

According to an audio recording of the clicks, they are ~495ms apart (10.434 - 10.929s), see red circle in the below picture pointing to PRF of ~2.02Hz.


I will see if i can match that (not sure what it is now without the mylar gaps in between the yoke halfs).


Itsu
   
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Re: Tiger's Blocking Generator replication « Reply #27 on: 2021-09-25, 11:00:21 »

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Quote from: Itsu on 2021-09-25, 09:38:26
Yes, i can see the decrease in amplitude in my setup, but this "turnover point" where it bounces back to an increase is missing here.
Well, at least you know what to look for.

Quote from: Itsu on 2021-09-25, 09:38:26
According to an audio recording of the clicks, they are ~495ms apart (10.434 - 10.929s), see red circle in the below picture pointing to PRF of ~2.02Hz.
Excellent. This is exactly what I had in mind.

Quote from: Itsu on 2021-09-25, 09:38:26
I will see if i can match that (not sure what it is now without the mylar gaps in between the yoke halfs).
I would expect the capacitance, resistance and inductance at the base of the BJT to have the most influence on the PRF. Could also be the turn ratio.
   
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Re: Tiger's Blocking Generator replication « Reply #28 on: 2021-09-25, 16:44:35 »

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Some initial tests shows that the PRF is changing in time.

Right after start (12V) its around 4Hz, after a few minutes (5) it passes through 2Hz, stays several minutes (5) around 1.8Hz, then ends around 0.8Hz.

Will do some more tests later today.

Itsu
   
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Re: Tiger's Blocking Generator replication « Reply #29 on: 2021-09-25, 17:44:01 »

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Quote from: Itsu on 2021-09-25, 16:44:35
Some initial tests shows that the PRF is changing in time.
Does the same input cap voltage always result in the same PRF ?

Quote from: Itsu on 2021-09-25, 16:44:35
Right after start (12V) its around 4Hz, after a few minutes (5) it passes through 2Hz, stays several minutes (5) around 1.8Hz, then ends around 0.8Hz.
Is the transition from the 12V to the 2V regime abrupt ?
   
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Re: Tiger's Blocking Generator replication « Reply #30 on: 2021-09-25, 21:08:32 »

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Quote from: verpies on 2021-09-25, 17:44:01
Does the same input cap voltage always result in the same PRF ?

Yes it does look like it, when inputting 6V i always have a certain PRF, same with 8V, 10V etc., see below picture 2 graph of the Inp Voltage v PRF.


Quote
Is the transition from the 12V to the 2V regime abrupt ?

Well, this transition was only there with certain earlier transistors AND with a Lower C1 (like 2nF).
Now that i am using a C1 of 48nF (to lower the ringing frequency to 30KHz) and the BF871, BF869 and now the KT805AM transistors, i get longer runtimes and do not have this transition, they have the ringing signal all the way to the end.


Below picture 1 shows the PRF and Input Cap Voltage versus runtime (14 minutes).

I have 48nF as C1, the 3 Germanium diodes, the KT805AM transistor and a 600nF cap as L1 to ground cap.

Itsu
« Last Edit: 2021-09-26, 09:36:27 by Itsu »
   
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Re: Tiger's Blocking Generator replication « Reply #31 on: 2021-09-25, 23:46:21 »

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Nice analysis!

The PRF vs. voltage relationship is linear from 12-6 Volts and between 1-3 Volts the PRF is constant.

Generally, it seems that this circuit auto-sweeps the ferrite until it hits some special combination of the PRF and a much higher frequency component of the ringdown.

This clever single transistor circuit performs a dual parameter frequency sweep, that otherwise would require your FG + PC for SCPI control.
   
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Re: Tiger's Blocking Generator replication « Reply #32 on: 2021-09-26, 01:45:38 »

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Itsu, you've mentioned that the different Transistors that you've used have
resulted in differing run-times of the unpowered circuit.

Have you determined what specifically about the various Transistors is the
reason for the differing run-times or "transition" capability?


Attached is the Data Sheet for the STN851-A which has some
very interesting characteristics.


---------------------------
For there is nothing hidden that will not be disclosed, and nothing concealed that will not be known or brought out into the open.
   
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Re: Tiger's Blocking Generator replication « Reply #33 on: 2021-09-26, 09:54:05 »

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Quote from: verpies on 2021-09-25, 23:46:21
Nice analysis!

The PRF vs. voltage relationship is linear from 12-6 Volts and between 1-3 Volts the PRF is constant.

Generally, it seems that this circuit auto-sweeps the ferrite until it hits some special combination of the PRF and a much higher frequency component of the ringdown.

This clever single transistor circuit performs a dual parameter frequency sweep, that otherwise would require your FG + PC for SCPI control.

Yes, but note that it takes only seconds to drop the voltage from 12 to 10 etc., so the first part of that "Inp Cap Voltage v Time" graph is more curved then shown.


Itsu
   
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Re: Tiger's Blocking Generator replication « Reply #34 on: 2021-09-26, 10:00:07 »

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Quote from: muDped on 2021-09-26, 01:45:38
Itsu, you've mentioned that the different Transistors that you've used have
resulted in differing run-times of the unpowered circuit.

Have you determined what specifically about the various Transistors is the
reason for the differing run-times or "transition" capability?


Attached is the Data Sheet for the STN851-A which has some
very interesting characteristics.

muDped,

no i have not looked at the difference in used transistors, but Kator also mentioned earlier that some specific parameters are important.

The "transition" is mostly gone at a lower ringing frequency (30KHz) which i use now.

Thanks for the PDF on that transistor, any hints on what is so interesting with it?

Itsu
 
   
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Re: Tiger's Blocking Generator replication « Reply #35 on: 2021-09-26, 13:20:17 »
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Hi Itsu,

Accidentally I found this picture.
It says that choke with inductance 10x of L3+L4 need to be added to the schematic.
Perhaps you would like to try this modification.

Regards,
Vasik

PS It says that C3 is 6x 2200uF 6V
   
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Re: Tiger's Blocking Generator replication « Reply #36 on: 2021-09-26, 15:36:01 »

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Quote from: Itsu on 2021-09-26, 09:54:05
Yes, but note that it takes only seconds to drop the voltage from 12 to 10 etc., so the first part of that "Inp Cap Voltage v Time" graph is more curved then shown.
Acknowledged but this time does not change the shape of the  "PRF" vs. "Inp Cap Voltage" graph, ...which is timeless.
   
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Re: Tiger's Blocking Generator replication « Reply #37 on: 2021-09-26, 16:43:35 »

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Quote from: Vasik041 on 2021-09-26, 13:20:17
Hi Itsu,

Accidentally I found this picture.
It says that choke with inductance 10x of L3+L4 need to be added to the schematic.
Perhaps you would like to try this modification.

Regards,
Vasik

PS It says that C3 is 6x 2200uF 6V


Vasik,

my L3 + L4 = 132uH, so that choke needs to be 1.32mH.

C3 would then be 6 x 2200uF = 13200uF (now having 1000uF).


I found a choke measuring 1.5mH which i will use and some 10000uF / 6.3V caps which i will use one for C3.


Itsu
   
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Re: Tiger's Blocking Generator replication « Reply #38 on: 2021-09-26, 17:41:17 »

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This mod significantly extended the run time as expected from 14 min. to presently 40 min and still running.

I will make some more measurements later today, but the 1.8Hz PRF is there most of the time.

It does take somewhat longer to "load" to 12V from the battery.

Itsu 
   
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Re: Tiger's Blocking Generator replication « Reply #39 on: 2021-09-26, 17:44:49 »
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800hz bursts filed with 30-40 kHz oscillations
   
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Re: Tiger's Blocking Generator replication « Reply #40 on: 2021-09-26, 17:45:50 »

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Quote from: Itsu on 2021-09-26, 17:41:17
Quote from: Itsu on 2021-09-26, 16:43:35
C3 would then be 6 x 2200uF = 13200uF (now having 1000uF).
This mod significantly extended the run time as expected from 14 min. to presently 40 min and still running.
C3 is over 13x larger now, so that is not surprising.
However, the amplitude increase which is demonstrated in the video at 3:10 is what we really want to observe.
   
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Re: Tiger's Blocking Generator replication « Reply #41 on: 2021-09-26, 17:46:20 »

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Quote from: Vasik041 on 2021-09-26, 13:20:17
Accidentally I found this picture.
It says that choke with inductance 10x of L3+L4 need to be added to the schematic.
Also, two additional annotations on this schematic state:
  • L2 40 turns of double wire.
  • L4 bifilar coil, the midpoint is its beginning and the end. (Verpies: The screenshot is cropped, so the entire one probably states: "L3+L4...")

...and I can't decipher the meaning of "800" in this one:
  • f= 800 (30-40 kHz)

P.S.
For those who are cyrillically impaired, the word "Шотки" means "Schottky".
   
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Re: Tiger's Blocking Generator replication « Reply #42 on: 2021-09-26, 18:05:57 »
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Quote from: Itsu on 2021-09-26, 17:41:17
This mod significantly extended the run time as expected from 14 min. to presently 40 min and still running.

I will make some more measurements later today, but the 1.8Hz PRF is there most of the time.

It does take somewhat longer to "load" to 12V from the battery.

Itsu

I rember that there were an opinion that gain in this circuit comes not from core, but from capacitors (e.g. due to dielectric absorbtion).
This might be interesting research topic.

-Vasik
   
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Re: Tiger's Blocking Generator replication « Reply #43 on: 2021-09-26, 18:25:41 »

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Quote from: Vasik041 on 2021-09-26, 18:05:57
I rember that there were an opinion that gain in this circuit comes not from core, but from capacitors (e.g. due to dielectric absorption)
Then we should be seeing coreless circuits exhibiting the same behavior.

Dielectric absorption is a real effect that manifests itself as a slow voltage increase across a discharged capacitor AFTER THE LOAD ACROSS THAT CAPACITOR IS REMOVED.  This effect can be easily observed with a high-Z voltmeter.

@Itsu
To test for this possibility, the "PRF vs. Voltage" graph of this circuit would have to exhibit directional hysteresis. 
In other words: a different shape when the voltage is increasing compared to when the voltage is decreasing.
   
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Re: Tiger's Blocking Generator replication « Reply #44 on: 2021-09-26, 19:32:35 »

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Quote from: Itsu
Thanks for the PDF on that transistor, any hints on what is so interesting with it?

What I find interesting about this new type of Transistor is its small size, its Collector Current Rating and its Low Voltage Switching Efficiency.

The Transistor is engineered to have High Current Gain and a Very Low Collector to Emitter Voltage Drop at Saturation.

 


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Re: Tiger's Blocking Generator replication « Reply #45 on: 2021-09-26, 19:52:22 »

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Quote from: verpies on 2021-09-26, 17:46:20
Also, two additional annotations on this schematic state:
  • L2 40 turns of double wire.
  • L4 bifilar coil, the midpoint is its beginning and the end. (Verpies: The screenshot is cropped, so the entire one probably states: "L3+L4...")

...and I can't decipher the meaning of "800" in this one:
  • f= 800 (30-40 kHz)

P.S.
For those who are cyrillically impaired, the word "Шотки" means "Schottky".


Concerning these annotations, i think they are the same as mentioned before in the below diagram from vasik:

L1 и L2 40 витков в два провода
L3 и L4 бифилляр средняя точка начало и конец

L1 and L2 40 turns in two wires
L3 and L4 bifillary middle point start and end     (google translate).



I was asking about L3 and L4 before as i do not see how they can be bifilar, so i have them "in series" now, with the midpoint the ending of L3 and
the beginning of L4 all CW.

But looking at the diagram from verpies, i can imagine how to wind them bifilar with the midpoint the ending of L3 and the beginning of L4.
I will have to rewind L3 and L4 to follow that.

Itsu
   
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Re: Tiger's Blocking Generator replication « Reply #46 on: 2021-09-26, 20:00:36 »

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Quote from: Itsu on 2021-09-26, 19:52:22
Concerning these annotations, i think they are the same as mentioned before in the below diagram from vasik:
L1 и L2 40 витков в два провода
L3 и L4 бифилляр средняя точка начало и конец
Yes and notice that the cropped screenshot did not mention L1 consisting of 40 turns, too.
This would change my translations to L1 & L2 being be wound with two wires, 40 turns each.

Quote from: Itsu on 2021-09-26, 19:52:22
I was asking about L3 and L4 before as i do not see how they can be bifilar, so i have them "in series" now, with the midpoint the ending of L3 and the beginning of L4 all CW.

But looking at the diagram from verpies, i can imagine how to wind them bifilar with the midpoint the ending of L3 and the beginning of L4.
That's how I understand that annotation about winding the L3 & L4:
   
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Re: Tiger's Blocking Generator replication « Reply #47 on: 2021-09-26, 21:24:13 »

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OK, i will rewind L3 and L4 that way tomorrow.


This evening, with the above modifications, it ran for 1 Hour 19 Minutes, starting at 12V, ending with 0.62V and with a PRF around 1.82Hz for ¾ of that time.

Voltage steadily decreasing over time, so no increase noticed.


Tomorrow i will show the Excel graphs.


Itsu
   
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Re: Tiger's Blocking Generator replication « Reply #48 on: 2021-09-26, 22:13:40 »

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To prove/disprove the Dielectric Soak/Absorbtion hypothesis, force the supply voltage to slowly increase over time and note whether the shape of the "PRF vs. Voltage" graph is the same as when this voltage is decreasing.
   
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Re: Tiger's Blocking Generator replication « Reply #49 on: 2021-09-27, 05:58:01 »
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One important thing: please note the capacitors voltage.
It's 6v but capacitors charged to 12v.
Over voltage cause  non-linear behavior in capacitors, similar to core saturation.
So when voltage decrease to nominal, capacity increases.
This could be source of "stabilization" effect when voltage decreases.

-Vasik
   
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