PHYS345 Electricity and Electronics

Standard Form to Polar and Back on the TI-82

Expeditious conversion of complex numbers between the standard form and the polar form will facilitate your ability to perform ac circuit analysis with accuracy and speed. The TI-82 class of graphing scientific calculator may be used to switch complex forms back and forth with the ANGLE function; the TI-85 calculator offers an even more efficient function CPLX The appropriate steps for operating the TI-82 calculator are outlined below.

Note that you may use whatever variable names you please; the desired angular units should be selected with the MODE function.

Front panel of TI-82 calculator Standard Form to Polar Form
Example: What is the polar form of 2.34 + j5.67?

Enter: 2.34 Real part of the complex number.
Key: STO>
ALPHA X 
ENTER
Store as variable X.
Enter: 5.67 Imaginary part of the complex number.
Key: STO>
ALPHA Y 
ENTER>
Store as variable Y.
Key: ANGLE 5
ALPHA X, 
ALPHA Y 
ENTER
First select the R->Pr conversion.
Display: 6.13 The magnitude of the complex number.
Key: ANGLE 6
ALPHA X, 
ALPHA Y 
ENTER
Next select the R->Ptheta conversion.
Display:   67.57   The phase angle.

Answer:   6.13 \/ 65.6deg

Polar Form to Standard Form
Example: What is the standard form of 12.3 \/ 45.6deg?

Enter: 12.3 Magnitude of the complex number.
Key: STO>
ALPHA R 
ENTER
Store as variable R.
Enter: 45.6 Phase angle of the complex number.
Key: STO>
ALPHA T 
ENTER>
Store as variable T.
Key: ANGLE 7
ALPHA R, 
ALPHA T 
ENTER
First select the P->Rx conversion.
Display: 8.61 Real part of the complex number.
Key: ANGLE 8
ALPHA R, 
ALPHA T 
ENTER
Next select the P->Ry conversion.
Display: 8.79 Imaginary part of the complex number.

Answer:   8.61 + j8.79


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"http://www.physics.udel.edu/~watson/phys345/class/7-polar-ti30.html"
Last updated Sept. 26, 1998.
Copyright George Watson, Univ. of Delaware, 1998.