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Author Topic: Testing the TK Tar Baby  (Read 1877039 times)

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #15 on: March 26, 2012, 12:55:38 PM »
What does "percent" mean? Well, it's PER cent, where the "cent" part means "100".

So if we have a quantity, call it A, and we want another quantity that is, say, 25 percent of A, how do we get there by calculation?

Well, first we take quantity A and DIVIDE it by 100. (PER cent means "divide by 100").  So in strange math symbols, we do A/100. The answer is one percent of A. Then we multiply that by the 25 part to arrive at the total (25 percent OF A) where, strangely enough, the "OF" part indicates a multiplication operation is to be performed somewhere.

Multiplication and division are inverse processes, and usually a division problem can be re-written as a multiplication problem and vice-versa.

(I rly hope that will be enough for the basic maths. I think it's important to clear up misconceptions and misconstruals that should have been taken care of long ago (like in the eighth grade algebra class that somehow got skipped) so that people are at least speaking a common language when they discuss complex issues.... like multiplication and division.)

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #16 on: March 26, 2012, 01:32:50 PM »
Significant digits, accuracy, and precision. Well.

In this age of digital everything, calculators that display twelve digits after a decimal point, DMMs that poke numbers at you as fast as you can read them off.... I often see people reporting calculations from instrumental readings that have TOO MANY digits to be realistic.

Accuracy means that the reading you get agrees with the "true" real-world state of affairs. Precision means how high-resolution a reading you actually get. Let's say I'm shooting at a target. All my shots fall into a tight group in the same place on the target. That's precision. But all my shots are three inches low and two to the left, even though I'm aiming at the bullseye in the sight. That's accuracy. They are different but interlinked.

Note that if a person claims that a particular value, call it "A", is equal to, say, 5.0789 volts.... the claim is that A is NOT equal to 5.0788 volts, nor to 5.0790 volts, nor any other value. But the true real-world value, under the claim, "could be" 5.07893, or 5.07896, or some other value in that finer range, and the claim would still be true.

Get the picture? In the first place, if my voltmeter reads 5.00 volts, and is accurate-- my precision is only good to three "significant digits". I don't know if the true value is 5.001 volts or 5.009 volts. So when I use that 5.00 volt figure in my calculations, I MUST ignore all extra digits of false precision that my calculator gives me. Citing them is the same as claiming I know the input data to equivalent precision... and I don't.

Now if I'm reading the values off the oscilloscope... I can only read the trace position value to within about half a "tick mark" accuracy, so that means any value I read will have only that level of precision, and if the scope's baseline or amplifier gain is incorrect, then all my readings will be inaccurate: not only "blurry" but also in the "wrong place". So my report of 5.00 volts, while "precise" in that all the figures do indicate real readings on an instrument... the true real-world value might be 4.00 volts, because I've set my baseline wrong or the scope's amplifier is out of calibration.

This is where the issue of "AC coupling" versus "DC coupling" on a scope trace could come into play. Where's the baseline that measurements are made from? Inquiring minds want to know.

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #17 on: March 26, 2012, 01:47:32 PM »
So... when _I_ speak about energy, power, Joules and Watts and Amps and Volts and all that jazz, you aren't going to have to learn some new strange language where words mean whatever I want them to mean and can change with the wind direction and relative humidity. I will  be using standard physics and electrical engineering terms and definitions, and if I go astray somewhere PLEASE somebody let me know.

If overunity device performance can't be tested, evaluated, or described using standard terminology and methodology -- yet they are to be built out of off-the-shelf simple components --, I am afraid we are sunk before we even get launched.

And no matter what my own personal weird theories are (I believe in pushing gravity, no dark matter, eleven dimensions, and a polarizable vacuum, for example, so there) you will not have to read about them, to understand how the Tar Baby performs.

evolvingape

• Sr. Member
• Posts: 478
Re: Testing the TK Tar Baby
« Reply #18 on: March 26, 2012, 02:50:15 PM »
There are still a few points about the open-source, help-to-replicate NERD RAT device I would like to understand.

First there's the value of the inductive-resistive load. I've seen inductances cited that are all over the map. I've seen 1.5 HENRY posted somewhere as the inductance of the load. This seems implausible to me based on the waveforms I've seen and what I know about the construction of common water heater elements. Also I have little confidence in instrumental measurements, especially difficult ones like inductance, that have been reported concerning that device.

Then there's the question of the battery capacity of the batteries that team used. I can't figure it out from the company's website catalog listing of the battery they used. The most reliable outside source I could find (humbugger) has it at 50 A-H, but the "official" reports of the NERD RAT device have it listed as 40 A-H. If battery draw-down tests are being considered, one would normally like to know the actual rated battery capacity, just in case someone cared enough to wonder if a 25 percent difference in actual capacity could affect such a test at all.
( 40 plus (25 PER cent of 40) = 50 ).

Hi TK, glad to see this claim is finally being rigorously tested as PER the scientific method!

About the batteries, we never did get a straight answer from Rosemary. Her donated set is the only set I have ever seen without a model number ?

http://www.overunity.com/11675/another-small-breakthrough-on-our-nerd-technology/821/

I'm delighted to see that everyone's answering TK's question.  I'm not sure I'd dare.  And IF that was a question by Glen Lettenmaier related to batteries - then here's the thing.  We were donated those beautiful Raylites.  But they have no ratings detailed on the battery itself.  We've tried to determine this and were advised that they're 40 ampere hour AND subsequently - that they're 60 ampere hour.  Don't know for sure and there's no way that we can find this out definitively.

We erred on the side of caution and have used the 60 AH rating for our paper.  Here's the 'extract' from our paper.

Some mention must be made of those aspects of the tests that have not been thoroughly explored. The first relates to the batteriesâ€™ rated capacity. The batteries used in these experiments have been used on a regular basis now, for over 18 months. They have been dissipating an average wattage conservatively assessed at 12 watts for five hours of each working day, during that period, continually subjected as they were, to both light and heavy use. Notwithstanding this extensive use, they have never shown any evidence of any loss of voltage at all. Nor have they been recharged except for two batteries that caught fire. Bearing in mind that the batteriesâ€™ rating is is not more than 60AH, there is evidence of out performance related to that rating.  However there has not been a close analysis of the electrolytic condition of the batteries, before, during or even after their use. This would require a detailed analysis of the supplyâ€™s electrolytic properties that is outside the scope of this presentation and expertise. Results therefore were confined to classical measurement protocols with the distinction that the energy dissipated at the resistor element was established empirically and as it related to the heat dissipated on that resistor.

So TK - YOU do the math.  And when you do this - factor in the continual use of 6 batteries only - as 2 were taken out of circulation some time back.  Or better still - average it at 7 batteries.  And then factor in that we've had possession of those batteries since late Jan early feb of 2010. Which means that its usage has been FAR more extensive than the conservatively assessed 18 months of continual use.  The usage has NOW actually spanned closer to 26 months.  And then try and explain why there is apparently absolutely NO LOSS OF VOLTAGE OVER ANY OF THE BATTERIES SINCE THE DAY WE TOOK POSSESSION.

Kindest regards,
Rosemary

As you can see when they "erred on the side of caution and have used the 60 AH rating for our paper." they even got that wrong and went the wrong side of "caution".

See Rosemary's blog post #232, January 23 2012, for more information on her calculations and battery ratings. I would copy it over but it is too long. Please promise you will not fall off your chair from laughing if you read it... it is a literal goldmine of scientific delusion.

http://newlightondarkenergy.blogspot.co.uk/

RM

• Hero Member
• Posts: 1843
Re: Testing the TK Tar Baby
« Reply #19 on: March 26, 2012, 03:18:06 PM »
To TK concerning the video http://www.youtube.com/watch?v=_CXWWupl0MU&list=UUZFlznLV3IyePfbc2TfDetA&index=1&feature=plcp (Electric OU: Supplement: MOSFETS... How do THEY work??):

TK, at the end of the video you are catching some oscillations (at minute 10:31). What do you want to say in relation to these oscillations? I am not getting your point (because my English is not good enough to dig insinuations and my knowledge in electronics is pretty shaky).

What do some people claim in relation to these oscillations? What are you claiming in relation to these oscillations?

(I am not criticizing, I jut want to understand.)

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #20 on: March 26, 2012, 06:49:17 PM »
@evolvingape:

Thanks for your input! I didn't remember that she had claimed 60 A-H capacity... the latest that I read, in post #666 is the quote and calculation which mentioned 25.6 million Joules in the one test against a batterypack of  5 (or was it six) 40 A-H capacity at 12 volts each, which calculation she finally retracted BUT SHE HAS NOT RETRACTED THE CONCLUSION that she had used more than the battery capacity in that one test.

A better demo of the oscillations that we are actually working with is here:

The circuit that the Tar Baby is modelled upon is the Rosemary Ainslie NERD circuit, which she claims produces COP INFINITY. (She was using the > symbol in there for a while !!) On the basis of this claim she is applying for at least two monetary prizes, one officially offered by this forum and another that's individually offered elsewhere.

HER circuit is claimed to 1) heat a load to useful temperatures 2) recharge the batteries while doing so and 3) run on and on and on, never depleting the batteries AT ALL, forever or until the end of time, whichever comes last, and 4) heals the lame and cures the sick. No, I'm just kidding about that number 4 part. The history of the NERD circuit is very interesting, and you will quickly  learn why I call my circuit the TAR BABY.

Even though I use the exact same... alleged.... circuit that she uses, EXCEPT for a few component substitutions, like the IRF830a instead of the magic IRFPG50 mosfet, and even though I achieve the SAME oscillations (parasitic feedback) caused by the SAME REASONS (stray inductance in the leads connecting the mosfets), and can achieve the SAME HEAT vs. time profiles in an inductive load, she affirms that my TAR BABY is not a replication of the NERD device. So that lets me off the hook totally and I can do whatever I like.

My claim about the Tar Baby is that it performs just like the NERD RAT device in all significant respects. If her device is overunity according to her calculations, since mine will produce the same data, then according to HER calculations.... well.... DO THE MATH (tm Rosemary Ainslie). Note that, in that case, since I am testing and publishing the results from MY TAR BABY..... I'll get priority in all disputes, since she released her design to "open source" yet refuses to show any tests of her own.... other than this one in this video here:

So far the traces I've shown on my Tar Baby correspond to the Blue trace (gate input) and the bottom GREEN TRACE, the mosfet common drains, shown in the above video on the Tek scope and in the screenshot -- with my reference numbers -- that I've attached below.

Please note that it has been demonstrated -- and admitted, finally, by Ainslie -- that the circuit diagram shown in the video is NOT the diagram of the device shown in the video, and there are other errors and misrepresentations in the video as well.

As far as I can determine I am using the presently accepted "correct" circuit diagram in my Tar Baby --- and I should be receiving my Magic Mosfets in a day or two, and at that point, except for the clipleads and threaded rods and white pegboard.... it will be very hard to tell any difference between the two devices. But we have her word that mine isn't a NERD, so it must be a Tar Baby. I'm even using a 10-ohm water heater element, OR.... a stack of sand resistors that come out to 50 W, 10 Ohm.

(edited a typo or too)

(Please don't be offended by the "shouting" emphasis. I'm trying to make points that might be able to penetrate someone -- not you two ! -- who seems to be extremely hard of hearing and vision. That is also the reason for the remedial EE and math posts I might make once in a while.)

(I also "claim" that the oscillations are irrelevant and are caused by stray wire inductance, and that if her device was constructed using commonly accepted layout and methods her oscillations, like mine... would go away or become very hard to obtain. If she made a few circuit changes they would be completely eliminated, her load would heat better, and she'd still not see her batteries draw down using the methods she allegedly uses.)

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #21 on: March 26, 2012, 07:19:11 PM »
Other than describing the "roots" of the Tar Baby, though... I really don't want to discuss the NERD RAT device. The time for that has passed for now... but will come again before too long. There's not much more that can be said that hasn't been covered in the last two months on her NERD thread in this forum (now locked, thanks Stefan) and also exactly a year ago on OUR, but with less noise.

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #22 on: March 26, 2012, 07:42:29 PM »
Let me just point out one thing about that scopeshot, though. The purple or pink trace, item 3,  is the battery voltage. Item 4 is this trace's "zero" baseline level. In item 8 you can see the amp settings for the channels, and see that the purple channel is set to 50.0 volts per major division. Looking at the scale divisions we see that the straight line of the purple trace is 1 major division plus one minor division above its baseline, for a value of about 60 volts, consistent with the DMM measurement in the video.
Now look at Item 9. This is the scope's "parameters" display where you can see what the scope's internal math is making of the traces. You can select various parameters for display here but the users have elected to display statistics like mean, minimum, maximum, and standard deviation here. Note that all you get for the purple trace in that box is its amplitude mean and a warning of "unstable histogram". This means that the trace is so noisy that the scope's math isn't coping with it reliably, and in fact even gets the amplitude wrong. The peaktopeak amplitude of the oscillation portion displayed can be estimated by looking at the number of minor scale ticks, representing 10 volts each, and simply counting them up.  I get about 80 v p-p for these oscillations, which again is an inductive effect caused by wire length. (Of course the mean amplitude will be decreased by smaller oscillations inside that noise, so maybe the scope is right here after all. At this sample rate it is impossible to tell.)
The battery voltage certainly isn't actually doing this. (For channel 1, the CVR, they are apparently calculating the statistics on the mean of the trace... getting a "mean of a mean" of an oscillation, more apparent nonsense).

Yet this is the data that was -- supposedly -- dumped to their spreadsheet for "analysis" that results in the conclusions they have claimed.

evolvingape

• Sr. Member
• Posts: 478
Re: Testing the TK Tar Baby
« Reply #23 on: March 26, 2012, 08:31:34 PM »
Hi TK,

Yeah, I don't wanna talk about the NERD circuit either. I think pretty much everything that "could" be claimed, has been claimed, just depends on the "when" you look.

A suitable analogy is a Kaleidoscope hooked up to a dremel, forever. (cos its running on a RAT psu!)

I am enjoying your posts and I am learning a lot from them, so thankyou.

Once you have established the run time of the Tar Baby on 5 A/h (Amps PER hour) batteries, assuming the same C rate, the calculations can be substituted for both 40 A/h and 60 A/h to give a good indication of expected performance. Unless your Tar Baby is COP infinity of course in which case it will not matter.

RM

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #24 on: March 26, 2012, 08:33:19 PM »
@evolvingape: that's an interesting quote from Ainslie. So she says the capacity is 60 Amp-Hours. And she says she's delivered 12 watts, five hours per day, every working day for 18 months. I usually figure 200 working days per year, so call it 300 working days. This is the input data, according to Ainslie.

Come, let us calculate together.

12 watts is 12 Joules per second. So, to calculate the energy transferred over the time interval, we multiply the Power in Watts by the Time in seconds.  12 Joules per second  x (60 seconds per minute x 60 minutes per hour x 5 hours per day x 300 days) ==  64 800 000 Joules. Call it 65 MegaJoules. (Note well, you NERD RATS, that before any math is even done, the UNIT DIMENSIONS of the input data and the result... agree. If you would only check this in your own "work"... or even understood it.... you would avoid much error in your calculations.)

That's not an unreasonable figure at all. And it's easy to see that if one allows for her proven tendency to...er... exaggerate or be a "tad out".... it's possible that perhaps not every working day was used, and that the device may have been inoperative for some stretches of time, and that the power level wasn't always 12 Watts and so on and so forth.

Now... if we only knew the actual capacity of her battery pack, we could make some interesting comparisons and further approximations. Note that the batteries won't drop  below 12 volts until they are almost completely depleted, and it is the "over 12 volt" reading that she constantly cites as evidence that they are still "fully charged".

So, using 60 A-H as the battery capacity, what do we have? For an individual 12 volt battery, we can get 12 volts x 60 amps for one hour, or one amp for 60 hours, same thing mathematically. So 12 x 60 = 720 Watts of power, for (60 seconds per minute x 60 minutes per hour x 1 hour) or 3600 seconds. So the energy in there is 720 Joules per second x 3600 seconds == 2.6 megaJoules, about. And then she has the six batteries (or seven, now, she says), so 7 x 2.6 megaJoules = a bit over 18 megaJoules in the batteries that they can deliver at or above a "charge level" of 12 volts each.

And 64.8 divided by 18 is only 3.6.

Personally I think the conclusion is clear. Even according to her exact claimed data, she has only used less than 4 times the battery capacity in that 18 months. Since we know that the FG can recharge the batteries.... well.....

(If we figure 10 watts at the load, 200 working days, 4 hours per day.... we get only about 29 megaJoules, less than twice the rated capacity. If we go to a three-day week, like a University class schedule, with summer and spring and holiday breaks..... we can easily get right down to the ACTUAL RATED CAPACITY of the batteries using a much more realistic test schedule than she reports. And the batteries will still test at 12 volts or above until nearly depleted, and a trickle of charge now and then from the function generator will keep them boosted above 12 volts even without actually substantially contributing to their charge state.)

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #25 on: March 27, 2012, 12:01:00 AM »
I picked up a 70 000 microFarad, 30 volt cap today at the surplus store. I'm not going to say how much I spent for it, it's embarrassing.

I also got a handful of H11D1 optocouplers and a bunch of sand and wirewound resistors to make loads and shunts with. I can even reproduce the 4+1 group of one-Ohm ten watt "shunts" or CVRs.

Ten Watts here? Four paralleled to give 40 Watts power handling in the CVR?  OK, fine. I guess that is just in case they do run the mosfets fully on by mistake and manage to expose the 10 ohm load to the full 72 volts along a low-resistance pathway for more than a brief pulse. But if they are averaging only 12 Watts at the load, as claimed.... they aren't running fully on, or they are on for a very short duty cycle only, or both, and don't need a 40 Watt CVR. All of that is conjecture, of course, since we have no reliable data from the NERD RATS.

I also got 5 nice ceramic tube , wirewound, 50 Ohm 12 Watt resistors, Clarostat VPR12F50 kind. I will be parallelling these to make a nice load that will fit better into my insulated Fleaker system than the water heater load does.  So I'll have a 10 ohm, 250 Watt equivalent load in there, which should be beefy enough to handle the anticipated maximum continuous current from the Tar Baby at 36 volts. Which is, neglecting the Rdss of the mosfets, by Ohm's law, I=V/R, so the current will be 3.6 amps, and by Power = I^2 x R, I get about 130 Watts dissipated by the stack at 36 volts and 3.6 amps ... so we be cool. Cooking with Hot Grease now, momma. With enough "oomph" if the mosfets do turn on to make tea or oxtail soup.

Now, if I could just find an old ox to chop the tail off of for my soup.....

ETA: Isn't anyone checking my math? OOPS..... five x 50 Ohm, 12 watt resistors gives us 10 Ohms all right, but only 60 Watts power handling capacity, not 250 like I figured above. So it's a good thing I've got them immersed in oil.... because I could exceed their power rating if I'm lucky.
« Last Edit: March 27, 2012, 05:45:37 AM by TinselKoala »

evolvingape

• Sr. Member
• Posts: 478
Re: Testing the TK Tar Baby
« Reply #26 on: March 27, 2012, 12:14:41 AM »
Hi TK,

Yes it's an interesting quote.

There is the issue that there were originally 9 batteries, and no data logging on hours run on which battery under what conditions, so the number you calculated for total energy available has unknown energy input from an additional 2 batteries included in the total for the 7 batteries.

Then you have the issue of surface charge on the plates. As we all know even a completely discharged battery if left alone overnight may recover enough to show a Voltage reading above 12V across the terminals under no load. This is why when people try to start the car and the battery dies, if you leave it 10 - 15 minutes and try again sometimes it will have enough energy to turn the starter and off you go. Never trust a battery is the rule of thumb.

Then as you mentioned the function generator is run from the wall socket and is capable of providing a float charge to the battery, which would probably keep it above 12V for a very long time while under a relatively tiny load.

Then you have the issue of potential desulfation of the plates from the oscillations:

http://www.reuk.co.uk/Battery-Desulfation.htm

Voltage spikes are the method of choice for reconditioning sulfated lead plates, restoring the charge holding capacity of the battery, not normally done while running a load at the same time though. The battery can even desulfate itself from it's own power if you hook the circuit up to the terminals, and recover charge storage capacity that way. You will still have to charge the battery though for a fully charged status of 13.2V, which is calculated as 2.2V PER cell, and 6 cells PER 12V battery, which equals 2.2V MULTIPLIED BY 6 cells = 13.2V fully charged.

RM

picowatt

• Hero Member
• Posts: 2038
Re: Testing the TK Tar Baby
« Reply #27 on: March 27, 2012, 01:29:39 AM »
TK,

Regarding your proposed optocoupler setup...  That would be fine if the MOSFETS were being switched on hard.  But they are not.

Q1 may be switching on fairly hard (and only briefly as per the RA waveforms) but the Q2 "quad array" is being biased into a somewhat linear region.  I believe .99 has touched on this.  Even with the FG at  -15 volts, the Q2 drain current at DC wll be limited to 300 ma or less due to the Vdrop across Rgen.  More likely it is between 100-250 ma.  Without knowing the FG open circuit voltage versus in circuit voltage, it is difficult to know the actual bias current used.  The variability of the gate threshold voltage also presents an unknown.

For DC and at 300 ma. bias, the FG 50 ohm would dissipate 4.5 watts, the 10 ohm (?) load .9 watts and the Q2 ""array" would dissipate around 17 watts (assuming a 60 volt battery set).    The parallel pair of 100 ohm output resistors in RA's FG (as per the schematic .99 posted) may not even be 100 ohms anymore, as 4.5 watts would be a bit much for them.  Opening the FG and inspecting/measuring these resistors is in order.  Possibly, if they have increased in value, the bias current is way less than one would expect from the Rgen of 50 ohms.  If they are intact, the FG can only do just above -15 and Ibias would therefore be under 300 ma.

For AC current, the FG output is bypassed by the 12,500 pf (or more) of the total Q1 and Q2 gate to source capacitance, hence you better stick with the IRFPG50's, as all that capacitance sets the AC gain of the Q2 common gate amplifier and passes the AC current to the battery negative (via the CSR).

Picowatt

MileHigh

• Hero Member
• Posts: 7600
Re: Testing the TK Tar Baby
« Reply #28 on: March 27, 2012, 01:39:48 AM »
TK:

If you do the capacitor test then it would be worth it to measure the capacitance of your bank of capacitors.  Many people reply on capacitance and inductance meters.  I will go out on a limb and assume that 100,000 uF is to large a capacitance for a capacitance meter to measure.  What do you do???  Plus you mentioned tolerance, an almost taboo term on the free energy forums.  And the tolerance of big electrolytic caps is what, +/-10%?  Perhaps +/-20%?

So you might get some oohs and aahs if you made a clip where you measured the capacitance via the RC time constant using your best multimeter.

Then you hope your your cap-based power measurement will be in agreement with the Clarke-Hess 2330 and with the Tek scope.  Convergence!  That's another important lesson for all.  Hasn't a whole year's worth of discussion all hinged on a single measurement method that many people considered highly suspect?

You asked about the inductance of the the inductive resistor.  The off-the-shelf RAT heating element had minuscule inductance.  So small it might be too low for an inductance meter.  That's a reasonable guess, I have never played with one.  I am going to guess in the tens to hundreds of nano-Henries.  Same thing for the heating element that you bought.  I would guess that you can just take the rule of thumb for inductance per inch of wire and apply it to both of those commercial heater elements.  I forget the rule of thumb, it' something like 10 nano-Henries per inch.  In both cases it looks like the inductance in the interconnect wires would be comparable to the inductance of the heating element.

MileHigh

TinselKoala

• Hero Member
• Posts: 13958
Re: Testing the TK Tar Baby
« Reply #29 on: March 27, 2012, 02:25:41 AM »
TK,

Regarding your proposed optocoupler setup...  That would be fine if the MOSFETS were being switched on hard.  But they are not.

Q1 may be switching on fairly hard (and only briefly as per the RA waveforms) but the Q2 "quad array" is being biased into a somewhat linear region.  I believe .99 has touched on this.  Even with the FG at  -15 volts, the Q2 drain current at DC wll be limited to 300 ma or less due to the Vdrop across Rgen.  More likely it is between 100-250 ma.  Without knowing the FG open circuit voltage versus in circuit voltage, it is difficult to know the actual bias current used.  The variability of the gate threshold voltage also presents an unknown.

For DC and at 300 ma. bias, the FG 50 ohm would dissipate 4.5 watts, the 10 ohm (?) load .9 watts and the Q2 ""array" would dissipate around 17 watts (assuming a 60 volt battery set).    The parallel pair of 100 ohm output resistors in RA's FG (as per the schematic .99 posted) may not even be 100 ohms anymore, as 4.5 watts would be a bit much for them.  Opening the FG and inspecting/measuring these resistors is in order.  Possibly, if they have increased in value, the bias current is way less than one would expect from the Rgen of 50 ohms.  If they are intact, the FG can only do just above -15 and Ibias would therefore be under 300 ma.

For AC current, the FG output is bypassed by the 12,500 pf (or more) of the total Q1 and Q2 gate to source capacitance, hence you better stick with the IRFPG50's, as all that capacitance sets the AC gain of the Q2 common gate amplifier and passes the AC current to the battery negative (via the CSR).

Picowatt

Thanks for your analysis, I really appreciate it. Your knowledge appears to exceed mine somewhat in these matters, so I'll just say that your estimates of maximum drain current attainable agree with my measurements. In fact without really cranking up the output of my F43 FG, which is capable of 40 V p-p into 50 ohms, I mostly stay under 200 mA as long as I am using a strict negative going pulse so that only the Q2 "gang of four" is active. However, I can operate my circuit in a mode, by varying offset on the FG, so that both mosfet sets turn on, and the oscillations can be seen on both phases of the signal, and the current can go up to 3 amps or more, mostly going through Q1 I think, from comparing temperatures. I'm not properly heatsunk so I only operate at those levels briefly, but now that I have the better load setup with the wirewound resistors, giving more inductance than the water heater element, I'll be pushing it a bit more.

I don't think I'm willing to buy an Instek FG of the same model as theirs. They cost about 220 bucks and I'm not rich. Besides.... I feel that the Interstate F43 is doing just fine, so far. It's an oldie but a goodie, and I keep it in good condition. Still.... the Instek is available locally if I do need to get one.

I'm not sure if I follow your reasoning as to why I should stick to the PG50. Are you saying that the PG50 may be necessary for some kind of battery charging from the FG to occur, and it might not if I use the 830a? Anyway, I'll be switching to the PG50 as soon as they arrive, and I'll be doing side-by-side comparisons like I did those many moons ago with the 2sk1548 in her COP>17 circuit.

The damn RF from the thing messes with both my little digital thermometers... I've had to start using an old analog bimetal type to get a reliable reading, with loss of precision and accuracy.

And of course, since I'm exploring these other modes as well, I'll try the optocouplers anyway. As long as I don't kill the oscillations....
because without oscillations there is no way that certain people will think I'm really doing what I'm doing, really.