Self accelerating reed switch magnet spinner.

[MileHigh]

TK:

Another thought or two about the issue of 1-ohm vs. 0.1-ohm for the current sensing resistor for the analog computer.

Using a 0.1-ohm resistor seems more "satisfying" as the design choice for the current sensing resistor because it disturbs the current flow through the circuit under test that much less.  I stated that I was "not comfortable" with the low voltages generated and the higher amplification required from the op-amp.  One more time I have to confess that I am not really sure if these are valid issues or not.  I have second thoughts about stating that the voltages wold be "low" for the op-amp differential input.  The whole point about the design of an op-amp is that the negative feedback reduces the differential voltage across the differential inputs to near-zero anyways.   For example, if the op-amp gain is one million, and the output is at six volts, then there is only a six microvolt potential difference across the inputs.

There is another biggie that I forgot to mention.  We know that the higher the gain for any amplifier, then the higher the noise is at the output.  Noise at the input gets amplified at the output plus the amplifier itself amplifies its own noise.  Supposing that there was a small amount of perceptible noise at the output of the first amplifier because of the high gain.  Well, it doesn't really matter!  The output from the first stage amplifier goes into a humungous RC filter that will squelch that noise to zero!  The second-stage amplifier will never see it!  Hence, 0.1-ohm may be the way to go.

Also, with a FET-input op-amp, this issue of bias compensation may be handled differently.  I was really talking about conventional op-amp inputs where you talk about a very tiny amount of bias compensation current.  There is no DC current flow for an FET input, and I don't know if they need bias compensation potentials.  I am also wondering if the silicon has been getting better and better over the years such that you simply don't have to worry about that issue at all.  I am not motivated to the point of going and reading the TL082 datasheet, sorry.

I suppose in a way that working on the bench is like riding a bike.  It would be fun for me to check every stage of that little analog computer and make sure it was working perfectly. Sigh....  It would be like old times!

One thing that I have never seen in my meanderings on YouTube is someone working with a digital logic analyzer.  Mind you, I have never searched on that.  The point being that you see a smidgen of work with digital logic by the free energy enthusiasts but never any mention of a logic analyzer.  For people that don't know, it's like a scope but instead for digital logic signals.  A typical "scope display" for a logic analyzer would display between eight and 20 digital logic signals.  They usually had two scope-equivalent analog inputs also.  When I used one you could transfer your waveforms onto a 3 1/2" floppy disk.  RJ-45 networking ports, USB, and USB flash drives were way way off in the distant future.

MileHigh

[TinselKoala]

Instrumentation amplifiers:
http://en.wikipedia.org/wiki/Instrumentation_amplifier

Logic analyzers:
http://letsmakerobots.com/node/31422

Mixed signal DSOs:
http://electronicdesign.com/test-amp-measurement/what-s-difference-between-mixed-signal-oscilloscope-and-logic-analyzer

[TinselKoala]

I've moved the sense coil to the underside/inside the rotor. Works great! I still am not seeing anything I can attribute to interaction between the sense and drive coils.

Later on I intend to test for interactions, without the rotor in place. I want to see if I can get feedback oscillations through coupling of the input (sense) and output (drive) coils.

[synchro1]

@Tinselkoala,


                    Warp factor quantum leap! A N-S-N-S magnet arrangement would allow you to work the power coil to the inside also, to gain power from both coil poles, along with the sensor coil at 90 degrees. You'd have to cut that screw and tonge depressor off, build a skirt and dangle it.

[TinselKoala]

@Tinselkoala,


                    Warp factor quantum leap! A N-S-N-S magnet arrangement would allow you to work the power coil to the inside also, to gain power from both coil poles, along with the sensor coil at 90 degrees. You'd have to cut that screw and tonge depressor off, build a skirt and dangle it.

Well... sort of. That's a couple steps ahead of where I'm at yet. Sticking with all one polarity magnets for now: how about this: Inside the rotor, a double ended drive coil, wound onto a tongue depressor with a central hole for the axle. The winding would be opposite for the two ends, so they would both present the same polarity on the ends. This would provide a drive pulse to two magnets instead of just to one.