Advanced Electricity and Magnetism Advanced Electricity and Magnetism Physics Help Forum May 27th 2018, 09:41 PM #1 Junior Member   Join Date: May 2018 Posts: 1 RLC Circuit Hello there, I've been reading about RLC circuits and I'm not understanding the sample excercise. https://user-images.githubuserconten...2d14e53489.png So, basically, we have Frequency, Resistance, Inductance,effective current i (we have the effective current of the resistor and the inductor together), and effective total voltage, and we know that the power factor is 0.9, we have to find capacitance First I started plotting graphs like this https://user-images.githubuserconten...abacafc6f0.png in order to find an idea or where the result is. I know from other sources that the Capacitance should be 7.7µF This is what I've tried, I understand that with the power factor I can get the ratio between real and apparent power, which is the same as the one between real and apparent Impedance, the resistance is 100 Ohms, that means the real part of the impedance is 100. L from the inductor is 0.3H, the Frequency given is 50Hz that means the angular velocity is 100*Pi, with the angular velocity times L we have the reactance of the Inductor, and that is 30*Pi, Since the inductor and resistance are in series we just add them 100+j(30*Pi) and that's the impedance from the first part of the circuit, what we need is to find capacitance, I know the amplitude of the voltage is 325V, and I know the effective value of the current of i (reistance-inductor) is around 1.67A, I have no idea how to find capacitor other than brute force. If the power factor is 0.9 and the circuit is a parallel one that means we need to find the admittance that gives us this value, right? 100 is the only real resistance but it is in parallel, so does the total impedance have also 100 as real value? I suppose I'm confused, about some ideas.  Tags circuit, rlc Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post Site Advanced Electricity and Magnetism 1 Sep 6th 2017 01:02 PM Fg370311 New Users 3 Dec 1st 2016 01:26 PM missyc8 Electricity and Magnetism 3 Sep 30th 2009 09:19 AM helloying Electricity and Magnetism 2 Apr 15th 2009 04:08 AM tribble1 Advanced Electricity and Magnetism 1 Mar 22nd 2009 08:18 PM 