[Amps] Accuracy of computer aided designs (or) garbage in = garbage out

Dennis12Amplify at aol.com Dennis12Amplify at aol.com
Mon Feb 17 11:34:58 EST 2003

 Back in the early 70's I went to the Consumer Electronics show in Chicago, 
and there was a high end musical instrument amplifier manufacturer handing 
out bumper stickers that said:

E = MC^2 (+ or - 3DB)

I Still have mine, and have moved it from job to job with me ever since!

 I have also worked with SPICE models and was shocked when I discovered that 
the models we were using considered diodes to be either on or off, like a 
SPST switch, with no barrier potentials to be overcome or any internal 
impedance whatsoever! 

 Any models I did find that actually took any barrier potentials into account 
used 0.7VDC as the absolute barrier regardless of temperature and still used 
the switch type of analysis where it was either fully on or fully off with no 
forward resistance or reverse leakage, and never considered different barrier 
potentials for Germanium or Schottky devices. I shudder to think of how spice 
would handle a Tunnel Diode!

 Of course that was a few years ago, and I'm sure everyone will tell me those 
parametrics are all accounted for in the models they use now! 

 Go ahead and fire away with your criticisms; I just put up my spice model of 
a blast shield that is impervious to anything as long as no one pulls the 
plug on my computer, or any of my ceramic tiles fall off, or my craft rolls 
over to it's unshielded side and vaporizes because no one ever considered 
more than a minimum amount of attitude adjustment would ever be necessary 
when they built those computer models.

Dennis O.

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