Post on 16-Dec-2015
2.2. Sinusoids
A sinusoids is signal that has the form of the sine or cosine function.
Consider the sinusoidal voltage.
2.2. Sinusoids
as a function of ωt
as a function of t
Sinusoids repeat itself every T seconds.
T is called the period of sinusoids.
2.2. Sinusoids
A sinusoids can be expressed either in sine or cosine function.
We can transform a sinusoids from sine to cosine or vice versa.
Example 2.2.
Calculate the phase angel between and . State which sinusoid is leading.
Solution:
Sam
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2.3. Phasors
A phasor is a complex number that represents the amplitude and phase of a sinusoid.
Before we completely define phasors and apply them to circuit analysis, we need to be thoroughly familiar with complex numbers,
A complex number z can be written in rectangular form as;
imaginary part
Real part
2.3. Phasors
The complex number z can be written in polar or exponential form as;
magnitude phase
z can be expressed in three forms;
2.3. Phasors
İn general;
Real part
imaginary part
Time-domain represantaion
Phasor-domain represantaion
Example 2.5.
Solution: Here is an important use of phasors for summing
sinusoids of the same frequency.
Current is in standart form. Its phasor is;
Example 2.5.
we need to express in cosine form. The rule for converting sine to cosine is to substract .
if we let , then