Okay, so now how do we connect the pick-up coil output to the 72 base input resistors of the 2N3904 transistors? Probably the easiest way to do this would be to use an NPN transistor in an "emitter follower" configuration. I am still concerned about the "fan out" to drive so many inputs. So perhaps something like one emitter-follower circuit per pair of coils (16 inputs). With nine drive coils you would need five emitter-follower circuits. Here is the Wikipedia link: http://en.wikipedia.org/wiki/Common_collectorHere is the graphic: The Vout of each of the emitter-follower circuits could connects to the 16 base input resistors of the 2N3904 transistors. The emitter-followers themselves could be done with 2N3904 transistors. Finally we come to the all-important tuning and how to do this. We have quite a bit of amplification in this circuit now and the power is being supplied by the source battery and not the rotor, which is exactly what we want. So to do the tuning all that you need to do is connect the output of the pick-up coil to one side of a conventional 500-ohm potentiometer. The other side of the potentiometer connects to ground. The wiper from the potentiometer would connect to the five inputs of the emitter-follower circuits. Now as you turn this single potentiometer, you can tweak the timing of the 10-coiler with ease. There will be almost to Lenz drag load on the rotor from the pick-up coil. Note that some of the resistance values are just approximations, they may need tweaking. I suspect that you could use an even higher resistance tuning potentiometer. Note also, that you don't even need to have the rotor turning to test and debug this circuit. You can even do the whole thing with just a multimeter, you don't really need a scope! MileHigh
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