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Lecture 10:RL & RC CircuitsNilsson & Riedel 7.1-7.6

ENG17 (Sec. 2): Circuits ISpring 2014

May 1, 2014

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Recap – Inductors / Capacitors

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Overview

• Natural Response– RL Circuits– RC Circuits

• Step Response– RL Circuits– RC Circuits

• General Solution• Sequential Switching• Unbounded Response

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Natural Response

Currents and voltages that arise from an inductor or capacitor immediately after being disconnected from a DC (direct current) source.

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Current in RL Circuit

After Open Switch

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Time Constant

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RL Circuit Example

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Voltage in RC Circuit

After Switching

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RC Circuit Example

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Overview

• Natural Response– RL Circuits– RC Circuits

• Step Response– RL Circuits– RC Circuits

• General Solution• Sequential Switching• Unbounded Response

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Step Response

Currents and voltages that arise when energy is being acquired by an inductor or capacitor due to the sudden application of a dc voltage or current source.

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Step Response in RL Circuit

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Step Response in RC Circuit

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Overview

• Natural Response– RL Circuits– RC Circuits

• Step Response– RL Circuits– RC Circuits

• General Solution• Sequential Switching• Unbounded Response

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Generalized Solution

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Overview

• Natural Response– RL Circuits– RC Circuits

• Step Response– RL Circuits– RC Circuits

• General Solution• Sequential Switching• Unbounded Response

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Sequential SwitchingDefined: whenever switching occurs more than once in a circuit

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Overview

• Natural Response– RL Circuits– RC Circuits

• Step Response– RL Circuits– RC Circuits

• General Solution• Sequential Switching• Unbounded Response

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Unbounded Response

Defined: A circuit response that grows, rather than decays, exponentially with time.• Possible with dependent sources

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Recap

• Natural Response– RL Circuits– RC Circuits

• Step Response– RL Circuits– RC Circuits

• General Solution• Sequential Switching• Unbounded Response