[0:01]Hi friends, welcome to my YouTube channel. If you haven't subscribed to my YouTube channel yet, please don't forget to subscribe. Today in this video, we are going to learn about the first topic in the third chapter of Network Analysis subject. The first topic name is Concept of Resonance in RLC Series Circuit. Or, Series Resonance, the same answer should be written. So, before we learn about series resonance, we need to know what resonance is. So, resonance means that if the applied voltage and the resulting current are in phase, then it is called resonance. In such a resonant circuit, the circuit behaves like a purely resistive circuit, and its power factor is also equal to unity. So, there are two types of resonance. The first type is Series Resonance, and the second one is Parallel Resonance. So now, let's write about series resonance. First, we will write the same story about resonance again. If the applied voltage and the resulting current are in phase, then that circuit is called resonance. And Series Resonance means, the resonance that occurs in a series circuit is known as Series Resonance. Next, we draw the RLC series circuit. The current will be leading or lagging the applied voltage, depending on the values of XL and XC.
[1:38]Next point is, if XL, which is inductive reactance, lags the total current, then the total current will be lagging the applied voltage.
[1:57]And when XC causes the total current to lead the applied voltage. In the next point, we observe that if XL is greater than XC, the circuit behaves like an inductive circuit. In the next condition, if XC is greater than XL, then that circuit behaves like a capacitive circuit. In the next point, we write the first point again. In our RLC series circuit, if the current is in phase with the applied voltage, then the circuit is said to be in resonance. In this circuit, our power factor will be equal to unity. Why is it equal to unity? Because the phase angle between the applied voltage and the resulting current will be zero degrees.
[2:44]So, cos of phi. What is the value of phi now? 0 degrees. Cos 0 is equal to 1, so unity power factor. Next, along with this, the net reactance will also be equal to zero. So net reactance means XL - XC = 0. The reactances will be there, right? XL and XC, they will be equal to zero. So we previously learned the formula for impedance, Z = square root of R square + (XL - XC) whole square. If the value of XL - XC becomes zero in this, then only R will remain. So the square root will cancel, and Z = R. Due to this, the circuit's complex impedance is equal to the resistance. So, Z = R, as it will be. Thank you, friends.
