Sinusoids are signals that have the form of a sine or cosine function. A sinusoidal current is called alternating current (ac) because it reverses direction at regular time intervals, having both positive and negative values. Circuits with sinusoidal current or voltage sources are known as ac circuits. Phasors can be used to represent sinusoidal voltages and currents, allowing them to be analyzed using complex number arithmetic in either rectangular or polar form. Phasors reveal the amplitude, frequency, and phase relationship between signals.

1. SINUSUIDS AND PHASORS

2. SINUSUIDS AND PHASORS
 A sinusoid is a signal that has the form of the
sine or cosine function.
 A sinusoidal current is usually referred to as
alternating current (ac).
 Such a current reverses at regular time
intervals and has alternately positive and
negative values. Circuits driven by sinusoidal
current or voltage sources are called ac
circuits.

3. SINUSUIDS
 Consider the sinusoidal voltage
 Where
 It is evident that the sinusoid repeats itself every T seconds;
thus, T is called the period of the sinusoid. We observe that
ωT = 2∏
 So

4. SINUSUIDS
 where (ωt + σ) is the argument and σ is the
phase. Both argument and phase can be in
radians or degrees.

5. SINUSUIDS

6. EXAMPLE

7. PHASORS
 Z can be represented in three different ways
Representation of Complex

8. PHASORS
 Addition and subtraction can be better perform in
rectangular form while multiplication and division can be
done in polar form easily.

9. PHASORS

10. PHASORS
INDUCTOR PHASE
RELATIONSHIP
CAPACITOR PHASE
RELATIONSHIP

11. VOLTAGE CURRENT RELATIONSHIP

12. Apply Nodal analysis techniques to find Vo in the circuit.

13. NODAL ANALYSIS

16. MESH ANALYSIS