Complex Number and Phasor Notation

A slecture by James Herman

Partly based on the ECE201 Spring 2015 lecture material of Prof. Borja Peleato.

Link to video on youtube

Questions and comments

If you have any questions, comments, etc. please post them below

  • The video claims to explain how to convert between complex numbers and phasors, but phasors ARE already complex numbers. The video is actually explaining how to transform complex numbers between cartesian and polar notation. Cartesian notation has the form $ a+jb $, where $ a $ is the real part, $ b $ is the imaginary part, and $ j $ is the imaginary constant (denoted $ i $ in many other fields). Polar notation has the form $ A*e^{j\theta} $, where $ A $ is the magnitude and $ \theta $ is the phase.
  • Phasors are a mathematical tool that simplifies the analysis of circuits in sinusoidal steady state by using complex numbers instead of real sines and cosines. Instead of dealing with voltages and currents that oscillate with time, we treat the circuit as if it had only constant (DC) voltages and currents, but these are complex. "Phasor notation" is therefore equivalent to "complex notation".
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