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MT-144. NETWORK ANALYSIS Mechatronics Engineering (13). Sinusoids and Phasors. Contents. Introduction Sinusoids Phasors Phasor Relationships for Circuit Elements Impedance and Admittance Kirchhoff’s Laws in the Frequency Domain Impedance Combinations Applications. Introduction.
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MT-144 NETWORK ANALYSIS Mechatronics Engineering (13)
Contents • Introduction • Sinusoids • Phasors • Phasor Relationships for Circuit Elements • Impedance and Admittance • Kirchhoff’s Laws in the Frequency Domain • Impedance Combinations • Applications
Introduction • AC is more efficient and economical to transmit power over long distance. • A sinusoid is a signal that has the form of the sine or cosine function. • Circuits driven by sinusoidal current (ac) or voltage sources are called ac circuits. • Why sinusoid is important in circuit analysis? • Nature itself is characteristically sinusoidal. • A sinusoidal signal is easy to generate and transmit. • Easy to handle mathematically
Sinusoids (Cont’d) • A period function is one that satisfies f(t) = f(t+nT), for all t and for all integers n. • The period T is the number of seconds per cycle • The cyclic frequency f = 1/T is the number of cycles per second
Sinusoids (Cont’d) • To compare sinusoids • Use the trigonometric identities • Use the graphical approach
Phasors • Sinusoids are easily expressed by using phasors • A phasor is a complex number that represents the amplitude and the phase of a sinusoid. • Phasors provide a simple means of analyzing linear circuits excited by sinusoidal sources.
Phasor Relationships for Resistor Phasor diagram Time domain Phasor domain
Phasor Relationships for Inductor Phasor diagram Time domain Phasor domain
Phasor Relationships for Capacitor Phasor diagram Time domain Phasor domain
Example 3 -Y transformation
Applications: Phase Shifters Leading output
Phase Shifters (Cont’d) Lagging output
AC Bridges (Cont’d) Bridge for measuring L Bridge for measuring C
Summary • Transformation between sinusoid and phasor is given as • ImpedanceZ for R, L, and C are given as • Basic circuit laws apply to ac circuits in the same manner as they do for dc circuits.