This is a quick and short how to guide to using calculators for complex number analysis, converting back and forth between rectangular and polar, and how to carry out complex math without making mistakes.
Every calculator handles complex numbers a little differently and it is up to you to be familiar with how yours operates.
For the Electrical Power PE Exam, we can classify calculators into two groups:
Calculators that cannot tell the difference between polar and rectangular
and calculators that can
For calculators that cannot tell the difference, you will need to practice the following:
Getting used to quickly converting all of your values to polar before multiplying and dividing, or to rectangular before adding and subtracting.
Verifying the magnitudes of a polar equivalent of a rectangular value using the Pythagorean theorem:
Verifying the angle of a phasor in rectangular form by using the trigonometry inverse tangent function:
And making sure answers are expressed in the correct form that matches the possible solutions which is typically:
Polar for current and voltage
Rectangular for impedance
Polar or rectangular for apparent power
For calculators that can tell the difference, you get the added benefit of:
Being able to add or subtract polar numbers from rectangular numbers and vice versa
Being able to multiply or divide polar numbers from rectangular numbers and vice versa
Being able to quickly convert from one form back to the other
Here is an example of using the TI30XIIS, one of the most common calculators, for working back and forth between polar and rectangular vectors for the Electrical PE Exam
When I took the PE exam, I successfully passed the first time using a calculator that could not tell the difference, and I like to believe that it gave me an advantage over students using more sophisticated calculators because it made sure that I really understood that math and theory behind polar and rectangular where as students using calculators that did the work for them may have been more prone to mistakes.
However, after replacing my calculator with one that can do the work for me, I have quickly changed my views because it
Saves a lot more time
Leave less notes to write down
Eliminates steps that you may make a mistake on when you are rushed
The two calculators that can tell the difference between polar and rectangular vectors are the
TI-36X Pro
Casio FX-115 ES
If you are anything like me, and grew up in the public school system in the Unite States, then chances are the TI-36X Pro will be the most natural and intuitive for you to use, however, some people do prefer the Casio FX-115 ES.
The good news is both are very cheap and can be purchased on amazon for under $20. The key is to find a calculator that works for you, and to bring the same calculator to the exam. A few days before the exam is definitely not the time to try out a new calculator.
TI-36X Pro on Amazon.com for $19.99
Casio FX-115 ES on Amazon.com for $15.29
Would you like to share?
Comment below and share your experience using various calculators for the Electrical Power PE Exam.
Be sure not to give away any specific exam questions or answers per the NCEES policy.
This was a benefit to me as I use TI-36X pro calculator as well. I think this is one of best calculator which everyone should have for specialty exams like this. Some of tricks were very helpful and will definitely reduce my time in solving problems. Thanks Zach for taking out the time for this video.
I’ve always been a “TI” person myself and sounds like Zach is as well. This article really helped my familiarity with this calculator for the exam so I wasn’t seeing this interface for the first time. Thanks Zach!!
I’ve always used TI calculators, but I for some reason decided I’m gonna become a FX calculator person. After watching your videos and following along with the calculations I returned the FX calculator and have been using all the hidden functions you’ve shown us on TI calculators during the course to solve the problems. Thank You for all the effort in helping us learn something new Zach!
In my opinion TI 36 X is the way to go. Much more intuitive.
These tricks helped, I’m surprised how much being comfortable with the calculator helps in solving problems quickly and efficiently.
The Casio fx-115Es plus has the ability to do this function.
Is there an advantage the TI 36 X has that the Casio fx-115ES plus does not?
Hi Youssef,
Both the Casio fx-115Es and the TI 36 X can perform just about the same functions, either are a great choice for the PE exam. Personally, I prefer and teach with the TI 36 X. I suggest using the calculator you are more comfortable and familiar with.
In the paragraph below, from the text above, there is a spelling error on United.
If you are anything like me, and grew up in the public school system in the Unite States, then chances are the TI-36X Pro will be the most natural and intuitive for you to use, however, some people do prefer the Casio FX-115 ES.
Either of these two is okay. I use Casio FX-115 ES.