Testing the TK Tar Baby

[TinselKoala]

Guys - I've yet again been advised to stay away from this thread.  It's really achieving absolutely NOTHING - and I know this.

In any event just let me explain this much. TK is WELL able to get that oscillation from Q2 with a CONTINUAL NEGATIVE SIGNAL applied to the gate. As are we  And that's only with the use of Q2.  IF there's a continual negative charge - and YET there's an oscillation - then he's yet to explain how the battery discharges current NOTWITHSTANDING the restriction imposed at the gate of the transistor - from that negative voltage signal applied. Remember that each positive half of each of those oscillations represents the current flow from the battery supply.  So. Where is the path for that?  Certainly not across that gate.

It's absurd that they pretend to have the answers.  They're nowhere near.  Nor are we.  But we at least have a consistent argument proposed for consideration.

Regards,
Rosemary

Let me add this while I can still modify this post.  I'm referring to the circuit that he uses with just one MOSFET.  Hope that's clearer.

Again
R

I want you to justify this claim. Show me where, exactly, in the "circuit that I use with just one MOSFET" that a negative signal is ever applied to the gate of that mosfet. You are here making a false claim about a circuit that you do not understand. And you are once again misrepresenting my work, drawing conclusions based on your exact backwards misrepresentation, and blathering those false conclusions and false claims on the public Internet.

You must either justify it and prove that it is true, or ADMIT THAT IT IS A LIE, or at least an ignorant mistake.

Attached below are an image of the Altoid, with the scope probe hooked up to the 2n7000 mosfet's GATE and the case ground, running on a CAPACITOR bank only, charged to 5.5 Volts, making oscillations, lighting an LED load and making a negative mean power product.

And a scopeshot of the GATE signal provided to the mosfet by the circuit, at 2 volts per division, with the ZERO BASELINE indicated in red.

Now, Ainslie.... you are wrong, so you must either admit it and publicly retract the claims based on your "error"... or continue to demonstrate that you are both a miserable liar and too ignorant to understand the workings of a simple circuit with five components.

What you continue to fail to understand is that this mosfet, like yours, is oscillating because of a NEGATIVE VOLTAGE APPLIED TO ITS SOURCE, along with the various inductances and capacitances involved.

[TinselKoala]

Hey, PW and .99-- remember the discussion about whether or not the areas of the current curve above and below the zero marker were equal or whether one or the other side would be greater, indicating net current flow in the greater direction? We did some analyses based on colored pixels that weren't very precise or definitive.

But how about this for an oddball idea: Compare the Current trace, AC coupled vs. DC coupled.  In other words, display the current trace accurately using DC coupling, then, without changing anything switch the channel to AC coupling. The integrating and coupling capacitor will move the trace either up or down.... until the areas above and below the baseline are equal. Or does it simply move the trace until the baseline is at the middle of the p-p voltage excursion?
Either way, the direction the AC coupled trace moves, either up or down, will be a good bit of information to have, because it will be another "check on the balance" of the sign of the current trace mean.
Just a random thought before sufficient coffee, so I will not be surprised if you both find it incoherent.

[poynt99]

I haven't got much time right now, on my way to a BBQ, but to quickly answer the AC/DC question; when switching from DC to AC, the trace will move either up or down until the AVERAGE of the wave form sits firmly on the zero reference line of the scope. This would equate to equal areas above and below the reference line.

I'll get to the "miswiring discovery" later.

[TinselKoala]

I haven't got much time right now, on my way to a BBQ, but to quickly answer the AC/DC question; when switching from DC to AC, the trace will move either up or down until the AVERAGE of the wave form sits firmly on the zero reference line of the scope. This would equate to equal areas above and below the reference line.

I'll get to the "miswiring discovery" later.

Right. So if one looked at the trace DC coupled, and then switched to AC coupled, the trace will appear to move either UP, DOWN or not at all wrt the zero baseline. If it doesn't move, then it was symmetrical in the first place: Average positive equals average negative.
If the trace moves DOWN when AC coupled, then the POSITIVE average was greater than the negative average when DC coupled.
And if the trace moves UP when AC coupled, then the NEGATIVE average was greater than the positive average when DC coupled.
So the AC/DC coupling feature could be used, as I thought, to see just that: whether the positive average is greater, less than or equal to the negative average.
Right? I mean I know this is unorthodox, but is it basically reasonable, and would it give a meaningful result? (This is one measurement where precise scope calibration would indeed be an asset. I don't really trust the 40 year old capacitors in the HP180 completely.)

[poynt99]

TK,

You could use the scope to roughly determine the average, OR, you could just connect your DMM on DC volts like I said almost two years ago, and get an accurate reading:
http://www.youtube.com/watch?v=-2KhGpmXPjc&feature=plcp