OKAY BOYS AND GIRLS!
I have tired of the Rosemary game. Let us put paid, as Rose would say, to the foggy bullshit and proceed to show what is really going on once and for all. The following simulation, done in a user-friendly version of P-Spice known as Tina Pro, will clearly illustrate several very interesting facts that I have been stating for the entire time I have been posting on the subject.
Here is what the simulation shows, indicates and proves:
1. In the present five-MOSFET circuit using the component values given by Rosemary wherever clearly and unambiguously stated and using reasonable estimates based on clues she has given, the circuit self-oscillates indefinitely at around 1.2MHz after one single sharp transition is made at the gate. That is to say that the input signal need only be one single pulse step function lasting one microsecond or less and the cirrcuit sets into steady oscillation forever.
2. When the scope probes are placed exactly as she has them, the waveforms obtained for Vbatt and Vshunt with the simulation are precisely the same as what Rosemary shows and DO NOT show the correct battery voltage nor shunt voltage. They are indeed far exaggerrated in amplitude and severely skewed in phase relationship and waveform from reality.
3. Because the simulator allows us to separate the R and L components of the load resistor and the shunt resistor, we can conveniently place our simulator scope probes directly across the true pure resistances of each and look at the real power in the load resistor and the true current in the shunt.
4. Because the simulator allows us to separate the batteries from their associated wiring inductances, we can also observe that the battery voltage is not a large AC waveform, but, as we would expect, a steady DC voltage with only a small ripple due to finite battery impedance.
5. Given that the simulation very closely agrees with Rosemary's presentation of waveforms and amplitudes when probed as Rosemary is probing it and given that it bursts into steady-state endless oscillation after even one single step-function stimulus to the gates and given that it does all this quite readily without any significant tweaking or fussing and over a wide range of variations in the inductances and MOSFET models used, it can be clearly learned that the drive waveform has virtually nothing to do with the circuit operation save for the one initial starting transition. The oscillation frequency is relatively insensitive to variations in the circuit values, indicating that it is primarily a function of the MOSFET parasitics and transconductance. This proves my and IONs theory that the circuit is operating in a well-known common-source feedback oscillator mode.
To be continued shortly with pictures!
Cheeseburger Humbugger
Author
Topic: The Rosemary Ainslie Circuit (Read 459795 times)
