On Sat, Jan 21, 2023 at 11:45 AM, Jacques Audet wrote:
I just did some simple simulations and yes it would certainly help to stabilize the 30 mV drive voltage.
Then the Rs value doesn't matter, as you wrote.
Even a blind squirrel can find a nut once in a while. :-)
>In all cases a feedback circuit could be designed and would add complexity.
The complexity is over my ability, I sometimes see the big picture and even a block diagram, but can't design.
Yes, but once designed, it's done, I don't know if the complexity is all that much, but again, I have no design ability.
Re: the negative effect of reactance of the drive transformer. I haven't understood, how the reactance affects the measurement
as long as the Drive voltage remains at 30mV. Maybe the problem is in the nature of the feedback required to keep it at 30mV,
as Frequency changes, when reactance is involved.
I'm sure you're aware, but a change in Rs also will cause the drive voltage to sag with High Q tests and rise with low Q tests because of the Rsource resistance. This is where I started to see the problem I thought could be corrected with feedback. I wanted to use the transformer output voltage to correct the non-linearity issues of the Transformer.
? I'm still not seeing how the Reactance prevents this, but that's my problem, just a lack of knowledge. (if I was 18 again, I would do education differently)
??????????????????????????????????????????????????? Keep up the work, I enjoy the time trying to understand, Mikek
