Consider a series RLC circuit. THe applied voltage has a maximum value of 230 V
ID: 2122054 • Letter: C
Question
Consider a series RLC circuit. THe applied voltage has a maximum value of 230 V and oscillates at a frequency of 71 Hz. The circuit contains a variable capacitor, an 860 Ohms resistor, and a 4.3 H inductor. Determine the value of the capacitor such that the voltage across the capacitor is out of phase with the applied voltage by 43 degrees.
My group has been trying to figure this one out for awhile now, we are torn between using the either cos(43) or tan(43). When using tangent of the angle we get a 278.2 as our answer but that is obviuosly wrong. If you could please help and explain, it would be much appreciated.
Explanation / Answer
frequency=71 Hz==>R=860 ohms==>L=4.3 H==>C=x==>XL=2*pi*f*L=1918.26 ohms
arctan((1918.26-1116.2)/860)=43 degrees==>C=1/(2*pi*71*1116.2)=2 uF
answer C=2 uF