Laplace Analysis 02

Analysis of a Series RLC Circuit Using Laplace Transforms Part 02

In Part 01 of this series I covered the following topics:

  • The phenomenon of ringing
  • How ringing can occur in circuits under certain circumstances
  • Why ringing can often cause problems for the circuit designer
  • How ringing can occur in a typical half-bridge topology during commutation
  • How the half-bridge can be represented as a series RLC which is subject to a step change in voltage.

I then demonstrated how Laplace Transforms could be used to analyse the series-RLC circuit. This led to an equation describing the current through circuit, i(t), in terms of R, L, C and t. The equation was found to accurately describe the phenomenon of ringing when compared with an analysis carried out using LTSPICE. The equation was also found to be dimensionally consistent.

At the end of Part 1 I promised to revisit the analysis and demonstrate how we could also derive expressions for the voltages across R, L and C – VR, VL and VC respectively. I’ll derive expressions VR and VL using both the Laplace and calculus methods, illustrating how the former is much easier than the latter.

Here is the link to the pdf:

Laplace Analysis Paper 02
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