Using Laplace to solve circuit analysis

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SUMMARY

This discussion focuses on using the Laplace transform for circuit analysis, specifically addressing the transformation of a DC voltage source. The Laplace transform of a DC source is represented as V/s, with a 12 V source modeled as 12/s. The importance of correctly reflecting the polarity of stored energy from an initial current, such as a 30 V supply, is emphasized. Participants seek a general procedure for applying Laplace transforms in circuit problems, indicating a need for clarity in methodology.

PREREQUISITES
  • Understanding of Laplace transforms in engineering
  • Familiarity with circuit analysis concepts
  • Knowledge of voltage sources and their representations
  • Basic skills in differential equations
NEXT STEPS
  • Study the application of Laplace transforms in circuit analysis
  • Learn about the step function and its role in circuit modeling
  • Explore the concept of initial conditions in circuit analysis
  • Review examples of circuit problems solved using Laplace transforms
USEFUL FOR

Electrical engineering students, circuit designers, and anyone involved in analyzing circuits using Laplace transforms will benefit from this discussion.

Cocoleia
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Homework Statement


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The Attempt at a Solution


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As you can see, the answer is given in the problem. I have the 0.8t par right but somewhere along the way I messed up. I'm not really to sure about how to solve these types of problems using Laplace. Is there a general procedure that I should be following that I am not?
 
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The Laplace transform of a DC source is V/s. Essentially it's modeled as a step function, "turning on" at time t = 0. So your 12 V source should be 12/s.

The voltage that represents the stored energy due to the initial current (your 30 V supply) needs to have its polarity reflect the actual direction of that initial current.

Otherwise you seem to be doing okay.
 
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