RLC Series Circuit Problem: Find V_source from V_R, V_L, V_C

In summary, to find the rms voltage of the source in an L-R-C series circuit, you can use the phasor diagram to determine the vector sum of the voltages of the components. Rms and peak amplitude voltage are proportional by sqrt{2}, so you don't need to convert between the two. The source voltage is related to the other voltages as Vs = sqrt{ Vr^2 + (VL - Vc)^2 }.
  • #1
nucleawasta
5
0

Homework Statement


In an L-R-C series circuit, the rms voltage across the resistor is 32.0 , across the capacitor it is 90.1 and across the inductor it is 51.5 .
What is the rms voltage of the source?


Homework Equations



Well there are lots of equations V_rms =V/sqrt(2)
V_R=IR
V_L=IX_L(I[tex]\omega[/tex]L)
V_C=IX_c(I/([tex]\omega[/tex]C)

The Attempt at a Solution



So what i did was convert all the values from rms into their amplitude voltages and summed them. Then took the resultant rms of that answer. This is not correct however.

I was using kirchhoffs rules of the sum of voltages around loop =0. Does this principle hold true in this situation?
 
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  • #2
For an AC circuit, the voltage across the source is equal to the vector sum of the voltages of the components. Using the phasor diagram, you can graphically determine the direction of the source voltage, if it leads the current or not, and how to find the vector sum of the voltages. Rms and peak amplitude voltage are proportional by sqrt{2}, so you don't need to convert to peak and then back to rms, just leave everything in rms and the source voltage will be in rms. The source voltage is related to the other voltages like this:

Vs = sqrt{ Vr^2 + (VL - Vc)^2 }
 
  • #3
GRB 080319B said:
For an AC circuit, the voltage across the source is equal to the vector sum of the voltages of the components. Using the phasor diagram, you can graphically determine the direction of the source voltage, if it leads the current or not, and how to find the vector sum of the voltages. Rms and peak amplitude voltage are proportional by sqrt{2}, so you don't need to convert to peak and then back to rms, just leave everything in rms and the source voltage will be in rms. The source voltage is related to the other voltages like this:

Vs = sqrt{ Vr^2 + (VL - Vc)^2 }

Thank you so much! I've ben stuck on this for so long.
 

FAQ: RLC Series Circuit Problem: Find V_source from V_R, V_L, V_C

What is an RLC series circuit?

An RLC series circuit is a type of electrical circuit that contains a resistor (R), an inductor (L), and a capacitor (C) connected in series. This means that the components are connected one after the other in a single loop.

How do you find the value of the source voltage (Vsource) in an RLC series circuit?

To find the value of the source voltage, you can use the formula Vsource = √(VR2 + (VL - VC)2), where VR, VL, and VC are the voltages across the resistor, inductor, and capacitor, respectively.

What is the significance of the voltage across each component in an RLC series circuit?

The voltage across each component represents the energy stored or dissipated by that component. The voltage across the resistor (VR) represents the energy dissipated as heat, the voltage across the inductor (VL) represents the energy stored in the magnetic field, and the voltage across the capacitor (VC) represents the energy stored in the electric field.

How does the source voltage (Vsource) change in an RLC series circuit as the frequency of the input signal changes?

The source voltage (Vsource) in an RLC series circuit is affected by the frequency of the input signal. At resonant frequency, the source voltage is at its maximum value, and as the frequency deviates from the resonant frequency, the source voltage decreases. This is because the impedance of the circuit changes with frequency, affecting the amount of voltage that is dropped across each component.

Can the source voltage (Vsource) ever be greater than the individual voltages across the components in an RLC series circuit?

Yes, the source voltage can be greater than the individual voltages across the components in an RLC series circuit. This can happen when the components have different phase shifts, causing the voltages to not add up perfectly according to the formula Vsource = √(VR2 + (VL - VC)2). This is known as a resonance effect and is commonly seen in AC circuits.

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