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Plot out of symbolic calculation

Forum|Forum|7 years ago
August 3, 2018
4 replies
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Hello Everyone,

I am an electronics engineer who has just started with Mathcad v15. I work on a sheet which calculates total power dissipation in a power supply. I have many input variables which help me to get the desired information - total power dissipation (Ptot) and predicted efficiency (Eff). So far, the calculation sheet works well.

The struggle:

Now, I would like to vary some input parameters and see in a plot how total efficiency change. For example, I want a plot with Iout on the x-axis and Eff on the y-axis. I have already spent half a day by googling but could not come up with a solution. Could someone review the sheet and come with a proposal how to make a Eff vs Iout plot, please? I expect that I need to somehow turn my equation into a function (numerical vs symbolic engine).

PS: A tip what to search on the forum will do too.I am not lazy 🙂

Best Regards, Jiri

1_mathcad_power_stage.zip

Electrical_Engineering

Best answer by AlanStevens

Something like the attached perhaps.

Alan

A

AlanStevens

Answer

19-Tanzanite

Something like the attached perhaps.

Alan

1_mathcad_power_stage_b.zip

J

Jip

Author

1-Visitor

Alan, this is great! What is the name of the magic you did with "k"? I understand how it works but I would like to study it more.

Thank you for your help and efforts.

A

AlanStevens

19-Tanzanite

k is a range variable. You can find out about them in the help facilities.

Alan

L

LucMeekes

23-Emerald IV

The best way is to make sure that your Eff calculation is a function of Iout, then you can plot it.

Here's an example:

Success!
Luc

W

Werner_E

25-Diamond I

Unfortunately Mathcad does not offer a way to turn a worksheet into a function automatically (a long standing wish).

So what you have to do is to create the functions yourself.

Every calculation which uses one of the input variables you would like to change later has to be turned into a function dependent on those inputs.

Here is a simple example. Instead of a static calculation of just one value

you turn the calculations into functions

J

Jip

Author

1-Visitor

@Werner_E, @LucMeekes: I see... This is probably what I need to do. However, the resulting function is going to be super long because I want to play practically with all parameters.