Circuit Analysis For Dummies

Chapter 14

Analyzing Second-Order Circuits

In This Chapter

Focusing on second-order differential equations

Analyzing an RLC series circuit

Analyzing an RLC parallel circuit

Second-order circuits consist of capacitors, inductors, and resistors. In math terms, circuits that have both an inductor and a capacitor are described by second-order differential equations — hence the name second-order circuits. This chapter clues you in to what’s unique about analyzing second-order circuits and then walks you through the analysis of an RLC (resistor, inductor, capacitor) series circuit and an RLC parallel circuit.

For a refresher on second-order differential equations, refer to your textbook or Differential Equations For Dummies by Steven Holzner (Wiley).

Examining Second-Order Differential Equations with Constant Coefficients

If you can use a second-order differential equation to describe the circuit you’re looking at, then you’re dealing with a second-order circuit. Circuits that include an inductor, capacitor, and resistor connected in series or in parallel are second-order circuits. Figure 14-1 shows second-order circuits driven by an input source, or forcing function.

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