Testing the TK Tar Baby

[picowatt]

I have not tried a multi turn Tx yet. I was gonna today but I ran out of round tuits.
The circuit is basically an induction furnace; maybe a multi turn coil will turn it into a tenpenny nail-melter.

TK,

If I recall, you stated the only major change in the waveform when entering SNM was a drop in freq.

Mark the distance at just beyond which you cannot get SNM and then either with a variable cap or small value fixed caps try pulling the xmit freq down to see if you can get SNM at just beyond the marked distance (or increase freq if needed).

Possibly the observed drop in freq is due to mutual loading or icreased current draw/Vdrop when in the near field so adjusting the freq may not help.

However, it is also possible the xmt/rcv are just slightly off freq and tweaking one or the other may increase range.

Also, see what effect supply voltage has on xmt freq.  If it drifts as Vbatt decreases it will be difficult to keep all tuned perfectly.  A 10 volt LDO regulator may be required.

Might be worth playing with.

How clean do the xmt waveforms look? 

PW

[TinselKoala]

A video koan:

http://www.youtube.com/watch?v=SRifRDbKp-0


Another:


http://www.youtube.com/watch?v=v2lTeGH-lws

[TinselKoala]

@PW: Yes, I've fine tuned the prototype, the one with the white spool chokes, by adding a small cap to the 60 nF stack and by trying different length loops. I've gotten it matched well to its receivers.
The one I'm showing here is still in the tuning stages and I'm about to do just what you suggest with a trimmer, if I can find an appropriate one.

I'll cover the distance/freq relationships in a video shortly, after I've had a cup of joe.

The waveform taken across the TX drains, with no receivers active, is nearly a perfect sinusoid. It is better than the F43's sine output, even. There is just a tiny ripple in the first 90 degrees; the transitions and zero crossings are clean. If I scope the individual drains wrt the source, I see the scope leads ringing, I guess, as each transistor shuts off its half-cycle, so there's that little ring-tail on the ends of the half-sines.

[mrsean2k]

I don't mind commenting on Rosemary's comment, but to be honest I've no idea what accusations I'm addressing.


As far as she goes on my responses to @TK's discussion, she's correct; I think I'm following it, and I think my comments are on topic (if not always correct).

But to be clear, I'm not at a complete standing start WRT understanding, I have some distant calculus, electronics and physics. Just enough to be able to chase down references from trusted sources and see that the claims and discussions by TK, PW et-al are consistent with them being domain experts. It isn't proof, but it's good evidence.

And more than enough to see that Rosemary's lack of knowledge and unwillingness to learn are leading her and her replicators down dead-ends. This is regrettable enough, but she's a serial liar. I'm of the opinion that it's only a lie if you don't believe it, and I don't believe she believes any of it any more.

I've had my run-in's with TK before, and there are matters of judgment on the behaviour and motives of others we discussed at the time that I'd still disagree with him on.

As far as his qualifications are concerned, fuck knows. Like it or not, when you choose to remain anonymous, you can make any claim you like about how well qualified you are, it doesn't mean shit - you're just an anonymous wonk like most other people. But he's been consistent in his claims, consistently correct in his references, consistently open in his working methods, meticulous in documenting what he does and presenting it, unafraid to correct and retract where necessary.

IOW every action is consistent with him having the qualifications he alludes to in the areas he claims. Good enough for me to treat him as if he's qualified.

Rosemary on the other hand is serially inconsistent in all of these areas. I weigh her comments accordingly.

[TinselKoala]

Thank you MrSean2k for giving us your explanation of your stance. It seems to be rather at variance with how Ms Ainslie represented your comments. I'm glad for your participation, as usual, and I rely on you, and others with a discerning mind, to let me know when and how I err.

I believe that the only person likely reading here who actually _needs_ the information that I have been imparting for the last several days with this series of _little_ essays... is Rosemary Ainslie. It is clear from my occasional dips into the Function Generator Anatomy thread that, even as late as this morning, there is still a great problem with the understanding of the basic issues of what voltage is, how it arises, and what current is and how it arises.  This is truly unfortunate. It illustrates that a cup that is overfull with kitchen slop and the discards from soupmaking.... cannot possibly receive and hold the pure and simple tea of Quantum Electrodynamics. Ainslie's strongly held, incorrect, notions of what voltage is and how current flows are clearly impeding her understanding of very basic phenomena in her own circuit-- even to the point that she denies their existence, when the evidence is written all over her data in pretty pastel digital phosphor.

I will be blunt: Rosemary Ainslie NEEDS to understand charge and its relationship to voltage and current. If she does not grasp the simple illustrations and allegories that show how charge, voltage and current actually arise and behave, she will have no hope whatsoever... and her interlocutors neither... of making progress in the FGA discussion. She is still holding and defending the idea that negative voltage is somehow a different thing than positive voltage, rather than a simple change in our viewing direction OF THE EXACT SAME thing.

For her, a FG "terminal" can "put out" a "negative voltage". And when there is "zero voltage".... nothing can happen. The concept of current Sources and Sinks is foreign to her conceptions.  Imagine getting her to believe that current can flow from a point that is at +12 volts, to a point that is at +9 volts, both with respect to a floating common that is at 100 volts above Earth ground, lighting up a 3-volt flashight bulb on the way without blowing the bulb. Impossible, she cries. How could one positive voltage "enable" a current flow to another positive voltage? Positive only flows to negatives. How could a voltage of +112 volts one one "terminal" and a voltage of +109 volts on the
"probe", not blow out a 3 volt bulb? How could any current flow at all, with such strong positives opposing one another?

This is how simple misconceptions of charge, what voltage and current are, and how charge flows in circuits absolutely block proper understanding of basic circuit behaviour. And on the other hand, when the basics of charge behaviour are understood, even at the level of the Voltage Game's simplistic analogy..... concepts that seemed intractably difficult and predictions that were at variance with actual experiment.... suddenly clear up, become obvious, and the predictions change and are now found to conform to reality.