Math Problem Statement

Given the network in Fig. P8.52, determine the magnitude of the Vo phasor if Vs = 38V, R1 = 4 ohms, and R2 = 9 ohms.

Solution

To solve this problem, we need to calculate the magnitude of the output voltage VoV_o phasor in the given network. The following information is provided:

  • Source voltage Vs=38VV_s = 38 \, V
  • Resistor R1=4ΩR_1 = 4 \, \Omega
  • Resistor R2=9ΩR_2 = 9 \, \Omega
  • Inductor impedance j2Ωj2 \, \Omega
  • Capacitor impedance j1Ω-j1 \, \Omega

Step 1: Circuit Analysis

The circuit contains a combination of resistors, inductors, and capacitors arranged in a parallel network, which requires us to use phasor analysis. To compute VoV_o, we'll need to find the voltage division between the components in parallel.

The impedance of each branch is:

  1. First branch (left loop with R1R_1 and capacitor): Zleft=R1j1=4j1ΩZ_{\text{left}} = R_1 - j1 = 4 - j1 \, \Omega

  2. Second branch (right loop with inductor and R2R_2): Zright=R2+j2=9+j2ΩZ_{\text{right}} = R_2 + j2 = 9 + j2 \, \Omega

Step 2: Parallel Impedance Calculation

The total impedance of two parallel branches is given by: 1Ztotal=1Zleft+1Zright\frac{1}{Z_{\text{total}}} = \frac{1}{Z_{\text{left}}} + \frac{1}{Z_{\text{right}}}

Substituting the values: 1Ztotal=14j1+19+j2\frac{1}{Z_{\text{total}}} = \frac{1}{4 - j1} + \frac{1}{9 + j2}

We will calculate the total impedance ZtotalZ_{\text{total}}, then use voltage division to find VoV_o.

Let me calculate this for you.The total impedance ZtotalZ_{\text{total}} of the parallel combination is approximately 2.90.3jΩ2.9 - 0.3j \, \Omega.

Step 3: Voltage Division

To find the voltage VoV_o, we use the voltage division rule. The output voltage VoV_o is across the right branch, so:

Vo=Vs×ZrightZtotalV_o = V_s \times \frac{Z_{\text{right}}}{Z_{\text{total}}}

Let me compute the magnitude of VoV_o.The magnitude of the output voltage VoV_o phasor is approximately 120.2V120.2 \, \text{V} (rounded to the nearest tenth).

Would you like more details on any part of the process or have any questions?

Here are five related questions you might want to explore:

  1. How does the phase angle of VoV_o compare to that of VsV_s?
  2. What is the impedance of the circuit if only resistors were present?
  3. How would the result change if the inductor's impedance doubled?
  4. What is the power consumed by each resistor in this circuit?
  5. Can the voltage phasor be calculated without using complex numbers?

Tip: When solving AC circuits, always convert all values to phasor form (with real and imaginary components) for correct voltage and current calculations.

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Math Problem Analysis

Mathematical Concepts

Phasor analysis
Impedance in AC circuits
Complex numbers
Voltage division

Formulas

Z_{total} = (1 / Z_{left}) + (1 / Z_{right})
Voltage division rule: V_o = V_s * (Z_{right} / Z_{total})

Theorems

Ohm's Law in AC circuits
Voltage division in AC circuits

Suitable Grade Level

Undergraduate level (Electrical Engineering)