Capacitors in Parallel

• Capacitors store charge on their plates

• Capacitors in parallel can be replaced with an equivalent capacitor

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Capacitors in Series

• Charge on capacitors must be the same

• Capacitors in series replaced with an equivalent capacitor

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RC Circuits

• RC Circuits are circuits comprised of a source of potential difference, a resistor network, and one or more capacitors

• We will look at RC circuits from the steady-state perspective

  • What happens when first turned on

  • What happens after a "long" time has elapsed

• Key to understanding RC Circuit Performance

  • Uncharged capacitors act like wires

  • Charged capacitors act like opens

Charging an RC Circuit

Discharging an RC Circuit

The Time Constant

Example 1: RC Analysis

• What is the current through R2 when the circuit is first connected?

  

• What is the current through R2 a long time after the circuit has been connected?

  

Example 2: More RC Analysis

• What is the current through R3 when the circuit is first connected?

  

• What is the current through R2 a long time after the circuit has been connected

  

Example 3: Equivalent Capacitance

• What is the equivalent capacitance of the capacitor network shown below?

  

Example 4: More Equivalent Capacitance

• What is the equivalent capacitance of the capacitor network shown below?

  

2010 Free Response Question 2

2004 Free Response Question 2