(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

R=250 L=6 C=15microf e(t)=300sin(50pi t) Find Z, phase angle, lead/lag, emf(215ms) (got all of this right) Voltage across inductor, capacitor and resistor, also show that the sum of the voltage across the elements at 215ms is equal to total emf at 215ms.

2. Relevant equations

XL=942 Xc=424 XL>Xc therefore current lags voltage, phase angle 1.12 rad emf@215ms=212V

Z=575ohm

3. The attempt at a solution

Up to this point I have everything correct. While solving the VL,Vc,Vr I use

VL=ImaxXL sin(wt+pi/2) = -339

Vc=ImaxXc sin(wt-pi/2) = 155

Vr=ImaxR sin(wt)= 91

I got Imax from Emax/Z = 0.52A.

emf(215ms)=300sin (50pi . 215 . 10^-3)= 212 . VL+Vc+Vr should be equal to emf at that time, mine does not equal to that.

What did I do wrong? Am I supposed to use the phase angle somewhere while calculating the voltage across the capacitor, inductor and resistance at a particular time( 215ms in this case)?

Edit:Also when using the phase angle, do we add or subtract it to (wt) depending on if the current is leading or lagging the voltage? How does that actually work out? Like what is a good way to decide + or - phase angle?

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# Homework Help: RLC AC circuit can't get right answer

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