Calculating Power Factor in and RLC Circuit

AI Thread Summary
To calculate the power factor in an RLC circuit with a resistance of 105 ohms, inductance of 85.0 mH, and capacitance of 13.2 μF connected to a 125-HZ AC generator, the impedance (z) can be determined using the formula z=sqrt[R^2+(X_L-X_C)^2]. The phase angle (ϕ) is found using tan ϕ = (X_L - X_C)/R, and the power factor is given by cos ϕ. The voltage of the generator is necessary to calculate current, but the power factor can still be derived from the phase angle. Clarification on the equations used for power factor calculation is provided, confirming that it is indeed cos ϕ.
rott3np3anut
Messages
1
Reaction score
0

Homework Statement


An RLC circuit has a resistance of 105 ohms, an inductance of 85.0 mH, and a capacitance of 13.2 μF. What is the power factor for this circuit when it is connected to a 125-HZ ac generator?

Homework Equations


Well I'm not completely sure which equations to use, so here's some I know:
z=sqrt[R^2+(X_L-X_C)^2]
where X_L and X_C are inductance and capacitance. R is resistance, z is impedanc

tan ϕ = (X_L-X_C)/R

p=1/2 VI cosϕ
My book gives me a different equation for power factor, so I don't know if I copied to notes wrong or if it's the same but written differently.

The Attempt at a Solution


Well I know enough to find ϕ. I then found z and was going to use that to find I, but that was when I realized the problem didn't give me the voltage of the generator. So I'm not sure how to solve for the current and the voltage without having one of them. Is there a different equation I should use for power factor? Please help!
 
Last edited:
Physics news on Phys.org
Hi rott3np3anut. The Power factor for an AC circuit is just cos\phi. Also tan\phi=\frac{X_L+X_C}{R}.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Calculation of current in driven series RLC circuit
Replies
8
Views
2K
Adjusting the Power Factor of an RLC circuit
Replies
20
Views
2K
How to calculate quality factor for RLC circuit?
Replies
6
Views
1K
Combined tensions of an RLC series circuit with AC current
Replies
3
Views
847
RLC Circuits - Q Factor and Amplitude
Replies
3
Views
2K
Width of Resonance in RLC-circuit
Replies
14
Views
3K
Solve RLC Series Circuit: V, f, L, C Given
Replies
16
Views
4K
Resonant frequency of L - R||C circuit
Replies
21
Views
1K
Calculating inductance of an LR and RLC Circuit?
Replies
8
Views
2K
Basic question about RLC circuits
Replies
32
Views
2K

Hot Threads

Recent Insights

Back
Top