


Learning Mathcad


WYSIWYG: There are no hidden programming steps or cell definitions (as in Matlab or Excel). Math in a Mathcad worksheet page looks 98% the same as it would in the textbook. (trick is how to enter math symbols not on a regular keyboard!)CALCULATIONS: Mathcad (in normal operating mode) is continuously trying to recalculate your input. It works from the top of the document to the bottom. Thus, if a formula is to be evaluated, all of its input information (e.g. the value of its parameters) must be entered ABOVE the formula on the page. If this is not done, and the formula contains undefined parameters, Mathcad will highlight the first error it finds in red (other errors, below, will not be highlighted until this one is corrected).
EQUAL SIGNS: Mathcad uses at least three different equal signs
Displayed as:
Typed in as:
Action:
= ctrl + = No action (except in solve blocks)
:= :
Assigns value on right of equal sign to variable or expression on left side. For instance, "a := 1" assigns value of 1 to variable a, "b := c + d" assigns value of c+d to b
= =
As in "a =" , asks Mathcad to calculate value of a (that is, you type in a = and it fills in computed value on right side)
CURSOR: Is like a word processor cursor in that it indicates where your new entries will be inserted. Is displayed as a vertical blue line.
DATA ENTRY POINT: Sometimes Mathcad knows that you must enter additional data and it draws a little darkened box at this point.
SELECTION: Sort of like selecting text in a word processor except is indicated by a horizontal blue line. Often starts as line under a single character. Move left and right with arrow keys. Expand by hitting space bar.
UNITS: You don't have to include units  but I strongly recommend it! Why? Because Mathcad keeps track of your input units and calculates not only the value but the units of your answers. If units are wrong in the answer, it means you typed in some input value or equation wrong. THIS UNCOVERS MOST ERRORS ! You will eventually remember Mathcad's builtin units (and define your own). But to start with, use the Menus: Insert / Units and Mathcad pops up a box allowing you to choose what you want.
CHANGING UNITS: If Mathcad's answer (on right side of = sign) is not in the units you want, click on the answer and a small box appears to its right. Enter in this box the units you want. Mathcad factors in your units (and if your units are appropriate, this leaves only your units).
YOUR VARIABLES / CONSTANTS: Be VERY careful naming your constants and variables! For instance, Mathcad has a builtin unit of Watts which it abbreviates as W. If you set up a calculation of W (the depletion width of a diode), your calculation will overwrite the Mathcad Watt unit. It will be gone! Lesson is use longer names for your variables and constants, for instance, here call the depletion width W_{depl}. Then you'll be safe.
TEXT: If you just want to write a comment (to label or explain your work), start by typing a quotation mark.
ALL THAT IS LEFT is how to enter strange math symbols. There are shortcut keys (many of which in the Short Tips section immediately below). However, to start with just go to View / Toolbars and select a whole lot of types. These pop up boxes displaying common symbols. Just click on the appropriate ones as you need them in the equation.
FINAL TIP: Mathcad 2000 can be a little unstable! Usually before it crashes it will warn you and give you time to save your work. However, sometimes it just crashes (especially when you try for pretty formatting, boxes and colors) so SAVE OFTEN!!
a) Units: Surest way of getting unit right is to use Mathcad menu: Insert / UnitsCommon microelectronics units:
Builtin
Doityourself
Amps: "A"
Ang: 10^{8.}cm
Centimeters: "cm"
eV: 1.6x10^{19 .} coul^{ .} volt
Coulombs: "coul" (not C)
Degrees Kelvin: "K"
Farads: "farad"
Seconds: "sec" (not S or s)
Volts: "volt"
b)Text and Equations:
Greek characters: cursor after character, ctrl+Gc) Equations only:
Square root: "\"Exponent: "^"
Inactive Subscript: cursor after character, "." (period), type subscipt
Active Subscript (index): cursor after character, "[", type subscipt
Prime: cursor after character, ctrl+F7
Not equal: ctrl+3
Prime: ctrl + F7
Vector (arrow over character): cursor after character, ctrl+"_"
Equal Signs: there are at least 3 different types I've used in lectures
= (type ctrl + "=") Mathcad does not try to do anything with this so it can be used in the simple statement of an equation. (Actually Mathcad can use such statements and then solve for values of variables consistent with such statements. See the "Solve.mcd" Mathcad example sheet):= (type shift + ":") Assigns value / expression on right side of the equation to the variable / expression on the left. Use this in setting up a problem
= (type "=") Type the variable / expression followed by a simple equal sign and this "asks" Mathcad to evaluate the left side (i.e. "What does it equal?)
You can capture above equation symbols in text by pasting equation into text box (however, pasting lone symbols, such as del/grad, can cause Mathcad program errors)
Introductory Lectures on basic and advanced Mathcad developed for my ENGR 162 classEveryday Mathcad (more than you probably need to know): MCD Version / PDF Version
4) Other Mathcad Worksheets I have developed
a) Mathcad Special Symbols Sheet (e.g. symbols for del / grad)b) Mathcad Sheet on Physical Constants (for semiconductor calculations)
c) "John's Appendix B"  semiconductor constants from Appendix B of Neaman's textbook
d) How to have Mathcad solve an equation or set of equations for the value of specific variable(s) Solve.mcd
e) How to do Mathcad loops and subroutines Trajectory_Program.mcd
f) How to do definite and indefinite integrals, and derivatives
g) How to plot a function that consists of two functions meeting at a point Composite_functions.mcd
h) Automated Mathcad tables of Silcon p and n Mobilities at 300C