Testing the TK Tar Baby

[hartiberlin]

Hi Rosemary,
TK is right.

You should have done the scope tests that he is now doing.


Until you are not able to show conclusive new data and battery charge status tests the Ainsley circuit is
in my view busted not to be generating additional energy.


Maybe TK can work out a  simple circuit diagramm with an additional 9 Volts helper
battery and a pot to produce a negative bias voltage, so the circuit will oscillate all the time.

Then this can be used instead of the function generator !

Maybe this additional battery plus pot needs a sharp switchon voltage graident to get the oscillations to work,
but this should be no problem with an additional switch...


So Rosemary now it is your turn  to  replicate TinselKoala´s  work and show that he is wrong.

And yes, he is right, 12 Volts lead acid batteries just sitting at just 12 Volts are almost discharged.
Fully charged they are about 13.8 Volts.

Just working on a thesis paper is not enough, if the technology behind it is only based on measurement errors...

Regards, Stefan.

[TinselKoala]

Here is some more work on driving the Tar Baby with an internal timer rather than an external function generator.

Fig.1:  The Tar Baby Revision C schematic reproduced again, showing the working, floating, externally powered 555 timer circuit that produces a strict negative-going gate drive pulse with oscillations, which I have been using for several days now.
ETA: The diagram shows 3 x 12 v main batteries, but I've been using 4, and of course with proper transistor heatsinking up to 6 batteries (72 volts nominal) can be used.

Fig 2: A 555 - based voltage inverter circuit that will allow the Fig.1 timer circuit to operate NON-floating and powered by the most negative battery in the main circuit's supply, with no external battery needed. This works but makes a bit of noise on the oscillations.... perhaps a filter stage to keep the oscillations from affecting the inverter itself  may be needed.

Fig 3: The Voltage Inverter installed on TarBaby and powering the 555 timer board for testing. Input power at the top, power connections to the timer board can be seen clearly. Red is positive, black is negative.
(I didn't have any 470 microFarad caps so I used 2 ea. 220 microFarad 35 volt caps in parallel for each of the 470s. Obviously component values aren't too critical.)


HOWEVER: since the TarBaby (and NERD) need that negative bias current on the Q2 source pins in order to make the oscillations..... neither Rev C alone nor the Rev C + Inverter will work in the positive pulse mode. That is... they work fine to turn mosfets on in that mode, but since they can't also provide the negative bias current at the same time... no oscillations are made.

I explain this need for negative bias current in the latest video, and show why a simple 555 circuit isn't going to work for both modes without some means for providing that negative bias current.

http://www.youtube.com/watch?v=XkNDYaFVc7g

(I'm posting this here _provisionally_ .... if the noise in the thread continues, then I will carry on further discussion on the YT comments and PMs and leave this thread for the fishes.)

[hartiberlin]

Hi TK,

why is a simple 9 Volts battery with a pot polarized inverted to the main batteries not enough to
put up the needed negative bias voltage ? If youi make the pot e.g. 1 Kohm you can
also drive a few milliamps as a negative bias current when needed...?

Then you would not need any floating circuit or any inverter to produce -12 Volts.

Regards, Stefan.

[picowatt]

TK,

What is the current draw on your 555 circuit while the TB is oscillating?

PW

[TinselKoala]

Hi TK,

why is a simple 9 Volts battery with a pot polarized inverted to the main batteries not enough to
put up the needed negative bias voltage ? If youi make the pot e.g. 1 Kohm you can
also drive a few milliamps as a negative bias current when needed...?

Then you would not need any floating circuit or any inverter to produce -12 Volts.

Regards, Stefan.

The negative bias current needed to make the oscillations can be as high as 200 mA or even higher. An external 9v battery will run down well before the main batteries begin to deplete, unless it's a big stack of 9 volt batteries.

Essentially though, that is what the circuit in Rev C does. It's a normal 555 timer, but with its output leads simply flipped: the Pin 3 output goes to the "negative" FG input to the main circuit, and the 555 ground goes to the _Positive_ FG input. This is why its supply must be floated (external, not grounded to the main circuit.) This arrangement produces a pulse that is "more negative" than the main circuit's ground -- a 555 positive pulse, going into where the FG's "negative" lead usually connects to the main circuit.

The negative bias current must be "more negative" than the most negative pole of the main battery. That's why a simple pot or 555 timer circuit powered directly by the most negative 12 volt battery in the main stack won't work. This is where the FG is inserting its current into the system, and this is where some means of getting "more negative" than the main battery's negative terminal is needed.

Please see my video explaining function generator polarity and current flow, as well as the most recent video linked in the post above. When the FG is set to make a symmetrical positive and negative pulse, and the "negative" output lead of the FG is connected to circuit ground (on either side of the shunt), then when the FG's pulse goes negative, the FG's "positive" output lead will actually be "more negative" than the circuit ground. That is, the FG's "negative" output lead is now positive with respect to the FG's "positive" output lead.  Confusing, isn't it. That's why I recommend watching the two videos.
In the latest video the amplitude and offset values of the FG are used to illustrate that, with the positive going drive pulse, there must also be a negative offset (not usually even visible on the scope trace) in order to make the circuit oscillate.