EEE/ETI 1202
CIRCUITS & NETWORK THEORY I
LECTURE 10
, Phasor algebra
• Sinusoids are easily expressed in terms of phasors, which are more convenient to work wit
than sine and cosine functions.
• A phasor is a complex number that represents the amplitude and phase of a sinusoid.
• A phasor diagram is a graphical representation of the phasors (i.e. voltages and currents) o
an a.c. circuit and may not yield quick results in case of complex circuits.
• However some techniques have been developed to represent a phasor in an algebraic (i.e
mathematical) form.
• Such a technique is known as phasor algebra or complex algebra.
• Phasor algebra has provided a relatively simple but powerful tool for obtaining quic
solution of a.c. circuits.
• It simplifies the mathematical manipulation of phasors to a great extent.
,Notation of Phasors on Rectangular Coordinate Axes
• j is an operator which rotates
phasor through 90° in CCW dire
without changing the magnitude o
phasor
• Since and its value cann
determined, it is called an imag
number. For this reason, any phas
its component) associated with
called the imaginary part.
• A phasor (or its component) alon
axis is not associated with j a
called the real part.
, The j operator and phasors
CIRCUITS & NETWORK THEORY I
LECTURE 10
, Phasor algebra
• Sinusoids are easily expressed in terms of phasors, which are more convenient to work wit
than sine and cosine functions.
• A phasor is a complex number that represents the amplitude and phase of a sinusoid.
• A phasor diagram is a graphical representation of the phasors (i.e. voltages and currents) o
an a.c. circuit and may not yield quick results in case of complex circuits.
• However some techniques have been developed to represent a phasor in an algebraic (i.e
mathematical) form.
• Such a technique is known as phasor algebra or complex algebra.
• Phasor algebra has provided a relatively simple but powerful tool for obtaining quic
solution of a.c. circuits.
• It simplifies the mathematical manipulation of phasors to a great extent.
,Notation of Phasors on Rectangular Coordinate Axes
• j is an operator which rotates
phasor through 90° in CCW dire
without changing the magnitude o
phasor
• Since and its value cann
determined, it is called an imag
number. For this reason, any phas
its component) associated with
called the imaginary part.
• A phasor (or its component) alon
axis is not associated with j a
called the real part.
, The j operator and phasors
