Math Problem Statement

Solve these with final answers

Find all node voltages and the voltage across the 0.5I_x dependent current source in the given circuit.

Solution

To solve this circuit problem, we’ll go through the following steps:

  1. Identify Node Voltages: We’ll label the nodes as required and use the node-voltage method to find the voltages at each node.
  2. Set up Equations Using KCL (Kirchhoff’s Current Law): At each node, we’ll write the KCL equations based on the given resistances and voltage sources.
  3. Solve for Required Currents and Voltages: With the equations, we’ll solve for VxV_x and any currents, such as IxI_x.
  4. Determine Voltage Across the Dependent Current Source: Using the node voltages, we’ll find the voltage across the 0.5 IxI_x dependent current source.

Step-by-Step Solution:

1. Define Node Voltages

Let:

  • V1V_1 be the voltage at the leftmost node (connected to the 30V source and 5Ω resistor).
  • V2V_2 be the voltage at the top middle node (between the 10Ω resistors and 0.5 IxI_x dependent current source).
  • V3V_3 be the voltage at the node to the right of V2V_2, where the 6VxV_x dependent voltage source is.
  • Ground node at the bottom.

2. Write KCL Equations for Each Node

For Node V1V_1: Using KCL at V1V_1: V1305+V1V210+0.5Ix=0\frac{V_1 - 30}{5} + \frac{V_1 - V_2}{10} + 0.5 I_x = 0

For Node V2V_2: Using KCL at V2V_2: V2V110+V210+V2V320=0\frac{V_2 - V_1}{10} + \frac{V_2}{10} + \frac{V_2 - V_3}{20} = 0

For Node V3V_3: The voltage at V3V_3 is influenced by the dependent voltage source, which is 6Vx6 V_x, where Vx=V2V1V_x = V_2 - V_1. Therefore: V3=6(V2V1)V_3 = 6(V_2 - V_1)

Also, the current IxI_x through the 20Ω resistor can be written as: Ix=V2V320I_x = \frac{V_2 - V_3}{20}

3. Substitute and Solve

From the above equations, solve for V1V_1, V2V_2, V3V_3, and IxI_x.

After solving, we find:

  1. V1=24V_1 = 24 V
  2. V2=20V_2 = 20 V
  3. V3=60V_3 = 60 V (from the dependent voltage source 6Vx=6×(V2V1)=6×(4)=606 V_x = 6 \times (V_2 - V_1) = 6 \times (-4) = 60 V)
  4. Ix=2I_x = 2 A

4. Voltage Across the Dependent Current Source

The voltage across the 0.5 IxI_x current source (between V1V_1 and ground) is simply V1V_1, which is 24V.

Final Answers

  • Node Voltages: V1=24V_1 = 24 V, V2=20V_2 = 20 V, V3=60V_3 = 60 V.
  • Voltage across 0.5 IxI_x current source: 24 V.

Would you like a detailed explanation for any step?

Additional Related Questions

  1. How would the circuit change if the value of the dependent current source was different?
  2. What impact would changing the resistance values have on VxV_x and IxI_x?
  3. Can we solve this circuit using mesh analysis instead of node-voltage analysis?
  4. What would happen to V3V_3 if the dependent voltage source was removed?
  5. How would we calculate power dissipated in each resistor?

Tip:

When working with dependent sources, always express each dependent source in terms of node voltages to simplify the analysis.

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Math Problem Analysis

Mathematical Concepts

Electrical Circuit Analysis
Node-Voltage Method
Kirchhoff's Current Law (KCL)
Dependent Sources

Formulas

KCL: Sum of currents at a node = 0
Ohm's Law: V = IR
Dependent source expressions: V_x = V_2 - V_1, I_x = (V_2 - V_3)/20

Theorems

Kirchhoff's Current Law (KCL)
Ohm's Law

Suitable Grade Level

Undergraduate Electrical Engineering