ENGR 2219 – Linear Circuits I
RL and RC Circuits
Natural Response
- Behavior is free of excitation (sources)
Natural Response of an RL Circuit
- Prior to t = 0
- The switch has been closed for a “long” time such that all currents and voltages have reached
constant values
- Then the switch is opened (t = 0 and later)
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ENGR 2219 – Linear Circuits I
RL and RC Circuits
- Time constant
- Voltage in the resistor
- Voltage in the inductor
- Power in the resistor
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ENGR 2219 – Linear Circuits I
RL and RC Circuits
- Power in the inductor
- Energy in the resistor
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ENGR 2219 – Linear Circuits I
RL and RC Circuits
Natural Response of an RC Circuit
- Prior to t = 0
- The switch has been at position ‘a’ for a “long” time
- The current in the capacitor is then zero
- Then the switch is moved to position ‘b’
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ENGR 2219 – Linear Circuits I
RL and RC Circuits
- Current in the resistor
- Current in the capacitor
- Power in the resistor
- Power in the capacitor
- Energy in the resistor
- Energy in the capacitor
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ENGR 2219 – Linear Circuits I
RL and RC Circuits
Step Response
- A DC voltage or current source is connected
Step Response of an RL Circuit
Step Response of an RC Circuit
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ENGR 2219 – Linear Circuits I
RL and RC Circuits
General Solution for Both Step and Natural Responses of RL and RC Circuits
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