Rosemary Ainslie circuit demonstration on Saturday March 12th 2011

[poynt99]

Which all brings me back to this answer to nul-points. 
- when I would have thought that the collapsing fields across the CSR result from Faraday's Inductive Laws.

Faraday's law is of course responsible for the voltage across any inductor as a result of the current through it changing, but Lenz's law determines the polarity of that voltage, and it is the polarity I was trying to emphasize.

What 'forward-biased' diode is this?  The zener body diode?  Or the diode that you've now put across the cap to replace the Q1 MOSFET?

The MOSFET body diode (if the Q1 MOSFET is used), and the diode I've replaced it with.

Because if you left the Q1 MOSFET as was earlier shown - then you actually don't get any 'squashing' or anything other than that clean sinewave shape. 

I am of course referring to the "CSR" wave form "shape" we are quite familiar with now. I would encourage you to view my recent post illustrating how the said diode limits the positive voltage excursion (in both circuits). In this sense, it "squashes" the otherwise narrower, higher amplitude, positive peak.

.99

[Rosemary Ainslie]

I encourage anyone following along and wanting to get the most out of the information being presented, they save and print out this diagram, which is the simplified single-MOSFET equivalent of the original 5-MOSFET version.

Please pay careful attention to the labeling and the connection/location of the "CSR" resistor (Lcsr1 and Rcsr1), and what used to be the function generator, and is now replaced with the fixed DC voltage source (Vbat2).

There are still a couple changes that can be made to simplify it even more, and I am still hoping one of the readers here might spot these. 

.99

My dear Poynty.  You're trying so hard.  Golly.  You've shown us a schematic with two shunts - one at the negative and one at the positive rail of the battery.  Could I impose on you to show us those voltages?  That may go some way to answering MileHigh's obsessive concern that somehow the functions generator is 'fudging' the results.  Because there is absolutely NO DIFFERENCE where you put that CSR.

Regards,
Rosemary

I'll get back to your other points in due course.  Lots of errors there Poynty Point.

ADDED
BTW - if there is a variation here then it is not representative of what is happening on our circuit.

and another point.  This is the schematic I'm referring to.
« Reply #932 on: Today at 03:35:16 AM »

[Rosemary Ainslie]

Well Poynty.  It seems that you are entirely ignoring most of my questions and those that you do acknowledge are answered incorrectly.  Pity.

So.  I'll start with the one that I thought was clearest.  Would you please oblige us by explaining how you plan to adjust the power from the supply without the use of what you refer to as Q1 - being the MOSFET that is positioned as traditionally applied?  While I'd be delighted to see variations of this circuit - as I'm sure we all would - I earnestly recommend that they're still able to perform some reasonable level of work. 

Then you say that Lenz Law determines the 'polarity"?  Since when did that happen?  Lenz law has nothing whatsoever to do with polarity.  That polarity was determined by Faraday and defined in inductive laws.  What Lenz law proposes is that the strength of those collapsing fields depends on the level of retained charge in those inductive components.  In fact his arguments go some way towards establishing those dreaded Laws that were imposed on Mr Faraday's discoveries.  Here's a Wiki link to this.

http://en.wikipedia.org/wiki/Lenz%27s_law

So.  With respect.  I rather suspect that your reference to this was to endorse those very laws that your results appear to defy.

Kindest regards,
Rosemary

[Rosemary Ainslie]

All,

With reference to Q1's function in the circuit, I hope this helps:

How a diode can effectively convert a wave form with a mean value of zero, to one with a mean value that is non-zero. This is one of the two functions Q1 is performing in the circuit via it's internal body diode.

This is a little confusing.  You show a CSR between two positive terminals of two separate supplies.  For any kind of current to flow you presumably have those batteries with different voltages.  So.  Let's assume that you can get a current to flow from the one to the other - then?  You apply a switch? is that it?  Or you change that signal to a negative?  I would have thought that if you can induce that tiny bit of inductance in the CSR to 'reverse' it's voltage (Faraday's Law) then it is unlikely to return to its source.  But.  If you used something with a little more inductance in it then you would, theoretically - not only have generated a sine wave but you would also be able to re-energise that supply.

So.  Far from 'converting a wave form with a mean value of zero' it's waveform would then first be greater than zero  and then less than zero and theoretically a pure sine wave would be the consequence.  This the more so as the voltage drop across the diode would apply in both directions. 

I'm probably missing your point.  But your recipe or explanation of 'How a diode can effectively convert a wave form with a mean value of zero, to one with a mean value that is non-zero' is posibly not the best example.  And I certainly do NOT  see that this is what Q1 is doing.  On the contrary.  Q1 is enabling the current from the battery supply.  For some reason there is a small period where this conduction is prevented.  That's where my own interest lies.  Personally I think it is to do with the amplitude of the setting.  But our amplitude is always 'full on' so that's still not the whole of it.  Hopefully the Tektronix will get to the route cause better.  At least we can experiment with shorter 'on' periods.

So.  And again.  This is absolutely NOT one of the two functions that Q1 is performing in the circuit via its internal body diode.  If only it were that simple.

(The other function is to provide additional D-G feedback capacitance in parallel with Q2's own internal Cg-d).

You really need to explain your terms.  What is a D-G feedback capacitance?  And why is this in parenthesis?  Is it your fall back argument?

This is a simple example that illustrates one of the effects Q1 has on the circuit. This ties in with my response to np's question about the positive portion of the "CSR" voltage. This hopefully gives you some insight into what can cause the MEAN negative voltage across the "CSR" resistor.

Let me know if anything does not seem clear and easy to understand.

So again Poynty Point.  I'm sorry but you're dealing with a gross amateur here.  If you can't be bothered to answer these points I won't blame you.  I'm sure that everyone reading here fully understands you.  But I don't.  And I certainly don't agree with you.  While I am delighted to see simplification of anything at all - I absolutely cannot follow this reasoning.  The more so as Q1 which you're so ANXIOUS to dispose of - is CRITICALLY required to conduct at higher energies.

Kindest regards,
Rosemary 

edited spelling.

[Rosemary Ainslie]

I encourage anyone following along and wanting to get the most out of the information being presented, they save and print out this diagram, which is the simplified single-MOSFET equivalent of the original 5-MOSFET version.

Please pay careful attention to the labeling and the connection/location of the "CSR" resistor (Lcsr1 and Rcsr1), and what used to be the function generator, and is now replaced with the fixed DC voltage source (Vbat2).

Which makes me rather alarmed Poynty Point - that you are now recommending this schematic to 'replace' our own.  Modify our own - by all means.  But I'm afraid if you go this route there is likely NO advantage whatsoever in this circuit.

I can't reference the diagram without seeing it but will do so when I've got that 'print out' that Poynty's recommending.  But there are so many obvious glitches and I'd be rather concerned that anyone go to too much trouble to build this proposed circuit when the schematic will most certainly not do what is required.  Unless I'm wrong.  I do hope so.  Doubly troubling - lol - when those 'pencilled in' comments all need such close review.  I'll deal with it when I've managed to get a copy of it for reference. 



Kindest regards,
Rosemary