Math Problem Statement

do number 1 like number 60

Solve for V_L using a process similar to Example-60.

Solution

To solve Question #1, where we are tasked with finding VLV_L using a process similar to the one in Example-60, we can apply the superposition theorem. This theorem allows us to analyze the circuit by considering one independent source at a time and then combining the results.

Step-by-Step Process

1. Circuit Setup

We are given two current sources and three resistors in the circuit:

  • 5A5A current source connected to a 6Ω6\Omega resistor.
  • 7A7A current source connected to a 2Ω2\Omega resistor.
  • The 8Ω8\Omega resistor is where we want to find the voltage drop VLV_L.

2. Apply Superposition Theorem

  • Deactivate the 7A source (consider only the 5A source first).
  • Deactivate the 5A source (consider only the 7A source next).
  • Sum the individual contributions of the two cases to find the total VLV_L.

Case 1: Deactivate the 7A Source (Open Circuit the 7A Branch)

In this case, only the 5A source is active. The equivalent resistance seen by the 5A current source is:

Req1=6Ω+8Ω=14ΩR_{\text{eq1}} = 6\Omega + 8\Omega = 14\Omega

The current from the 5A source will flow through both the 6Ω6\Omega and 8Ω8\Omega resistors (series connection), and the voltage across the 8Ω8\Omega resistor is given by:

VL1=IR8Ω=5A×8Ω=40VV_{L1} = I \cdot R_{\text{8}\Omega} = 5A \times 8\Omega = 40V

Case 2: Deactivate the 5A Source (Open Circuit the 5A Branch)

Now consider only the 7A source. The equivalent resistance seen by the 7A current source is:

Req2=2Ω+8Ω=10ΩR_{\text{eq2}} = 2\Omega + 8\Omega = 10\Omega

The current from the 7A source will flow through both the 2Ω2\Omega and 8Ω8\Omega resistors (series connection), and the voltage across the 8Ω8\Omega resistor is:

VL2=IR8Ω=7A×8Ω=56VV_{L2} = I \cdot R_{\text{8}\Omega} = 7A \times 8\Omega = 56V

3. Combine Results from Superposition

Since the two sources have opposing directions, we subtract the voltages:

VL=VL2VL1=56V40V=16VV_L = V_{L2} - V_{L1} = 56V - 40V = 16V

Final Answer:

The voltage across the 8Ω8\Omega resistor is VL=16VV_L = 16V.


Would you like further details on any part of this solution, or do you have any questions?


Here are five follow-up questions based on this problem:

  1. How would the result change if the direction of one of the current sources was reversed?
  2. Can we solve this circuit using Thevenin's Theorem instead of superposition?
  3. What is the power dissipated by the 8Ω8\Omega resistor?
  4. How do we handle circuits with dependent sources when applying superposition?
  5. How would the voltage VLV_L change if the 8Ω8\Omega resistor was replaced with a 10Ω10\Omega resistor?

Tip: When applying the superposition theorem, always deactivate independent sources by replacing voltage sources with short circuits and current sources with open circuits.

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Math Problem Analysis

Mathematical Concepts

Superposition Theorem
Series and Parallel Resistors
Circuit Analysis

Formulas

Ohm's Law: V = I * R
Superposition Theorem: V_L = V_{L1} + V_{L2} (taking into account current source effects separately)

Theorems

Superposition Theorem

Suitable Grade Level

Undergraduate - Electrical Engineering