Blind simulation without understanding

[Tim Williams]

Obviously there's feedback of a sort, but not of a kind where you
could fiddle with the phase shifts.

http://home.planet.nl/~sloma000/0344_001_Baxandal.pdf

Just because the loop is closed doesn't mean the differential equations
aren't there. You can gain access easily enough by controlling gain or
bias (manipulating the voltage or current into the base supply, or varying
the feedback voltage through various methods: pot, variac, old school
rotating-axis "tickler" coil, etc.).

For instance, a high impedance bias supply could allow the base supply
voltage to vary (large resistance or CCS, with servo if required), and the
V-I characteristics would then be easily observed (impedance, step
response, squegg damper "best values", etc.).

Tim

 

[josephkk]

Years ago I bought Mathcad, but found it quite cumbersome to use. If
I can't solve an equation on paper, I use Excel or, quite often now,
simply use PSpice... the behavioral modeling capability is so good, I
can set up and solve a transcendental equation in minutes.

Last time i was pounding Mathcad i was doing a simulation with it. Got
the job done too. I found the user interface to be fine, just very
different from everything else i had ever used, well until recently,
Macsyma is rather similar.

?-)

 

[josephkk]

I haven't tried it since DOS days ;-)

...Jim Thompson

I find the GUI version a lot easier to deal with. I don't have to
remember all the "abbreviations" and their usage rules. If i can find my
sim and a 'puter to with Mathcad loaded i will make a pdf and send it to
you. Unless you ask for it this will be low priority.

?-)