RLC Circuits are really complicated. That was the first thing that popped into my mind when Sir Baldo began discussing RLC Circuits, a circuit involving an AC source, a resistor, inductor and capacitor. As opposed to the topics that we have discussed for the past 6 experiments, the treatment for this one was more mathematically rigorous.
Anyways, at least we did not have a quiz that meeting, due to the fact that lack of time translated to lack of postlab quiz, so a take-home quiz was given to us.
The lecture that meeting was long, I think the longest it has ever been. It was understandable, though, because there are a lot of things that are needed to be tackled to fully describe an AC circuit. Since the voltage provided by an AC source is not constant (unlike DC), the current is not constant too, so normal methods for DC circuit analysis cannot be applied. Here, tools such as phasor diagrams and wave functions (sines and cosines) are used. It's a lot more difficult than DC. But weirdly, it looked a bit more appealing to me than DC. Still, I do not get AC that much because we have yet to tackle it in lecture class (wait, I don't think lecture class is not much help either), or err I have yet to read about it in the textbook. Another new circuit device introduced in class is the inductor, which by what I understood is a device that resists large changes in current by inducing an emf (thus a current) opposite the large change in current. Reactance (X) was also introduced. It was said to be the opposition of a circuit element to a change of electric current or voltage by the capacitor or inductor. Also, impedance (Z) was discussed. In an AC circuit, it acts as the "total resistance", and it can be plugged into Ohm's Law. Impedance, in terms of reactance of the inductor and capacitor, and resistance of the resistor, is:
Resonance of the series RLC circuit was the main thing that was the subject of the experiment. At resonance, the maximum current is obtained, and the frequency that corresponds to resonance is called, surprise, resonance frequency. Also, at resonance, the equivalence of inductive reactance and capacitive reactance is observed, and, due to this, the impedance is at a minimum.
The experiment was quite easy, as opposed to the concepts it showed. Basically, what we had to do was adjust the frequency of an AC source output and observe what happened to the voltage across the source, the capacitor, the inductor, the resistor, and the inductor-capacitor, and also the current across the circuit. We obtained the frequency where maximum current was obtained and called this the resonance frequency. We did this procedure with 1 capacitor, 1 inductor, and 2 resistors, one at a time.
We made use of the whole period and extended a bit, showing how time-demanding the experiment this meeting was. That was basically it for that meeting.
So for my thoughts: This was the first time I was introduced to AC circuits in my life, and I must say, I am a bit confused about it.:S As the semester progresses and we dig deeper into the world of electromagnetism, I get more and more "O_O" (I have no word for it, so I present a face). I really don't think that electromagnetism is my niche in the physics world, mainly because I can't really say I'm excellent at it and that much enthusiastic about it. All I can give is hard work and perseverance, and I hope that it pays off in the end.
