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setting variable for stationary vs time-dependent study in same project

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I have a component definition for an electrostatic potential constraint:

Vgate = 100 * (1 - exp(-t/3e-9))

This ramps up the gate bias to 100 volts with a time constant of 3 nsec.

However, I'd also like to do a stationary study in addition to the time-dependent study. When I run the stationary study I get:

"Undefined variable: t"

Ideally I'd like to be able to do two studies: one time-dependent, another stationary with the time also ramped as a parameter. Alternately I could explicitly ramp Vgate in the stationary study with the exponential time dependence applied to the time-dependent study.

As it stands I need to redefine the boundary condition depending on which study I am using.

Any help to this seemingly super-basic question?

thanks,
Dan

2 Replies Last Post Apr 5, 2016, 6:42 p.m. EDT
Edgar J. Kaiser Certified Consultant

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Posted: 8 years ago Apr 5, 2016, 5:47 p.m. EDT
Daniel,

just define a parameter t in the parameter table and assign a value that is suitable for the stationary step. t will be overwritten by the time dependent study solver.

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Daniel, just define a parameter t in the parameter table and assign a value that is suitable for the stationary step. t will be overwritten by the time dependent study solver. Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com

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Posted: 8 years ago Apr 5, 2016, 6:42 p.m. EDT
Thanks!

Key is it's a parameter and not a variable. I'd tried the latter.

Dan
Thanks! Key is it's a parameter and not a variable. I'd tried the latter. Dan

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