Solving DC problems

Example

Resistors R1, R2, R3 in the circuit below are connected in parallel. Calculate the total resistance.

Solution

i) We will solve the problem first by entering the equation for R. Write in the Interpreter

R := 1/( 1/R1+1/R2+1/R3 )

R = , Then press enter

The Interpreter will give the result,

R = [545.4545]

Since we have a schematic file open, we can access variables derived from the component name labels--R1, R2, and R3, for example. Click on the menu to Settings/View Symbol Table to view which variables are available to you.

ii) We will define a function to compute the total resistance of arbitrary parallel connected resistances labeled R1, R2, R3. The Interpreter’s Function declaration is used to solve more complicated problems. The syntax of the function declaration is:

Function FunctionName(parname1,...,parnamen);

Begin

function body

End;

The function that computes the parallel resistance is:

Function Parallel( r1, r2, r3 );

Begin

Parallel := 1/( 1/r1+1/r2+1/r3 );

End;

For a numerical solution based on the values of R1, R2, and R3 in the underlying schematic, type the following and press Enter:

Parallel( R1, R2, R3 )

See the result:

=[545.4545]