Summary

• Series circuits
• Parallel resistors
• Kirchhoff's laws

• Written Quiz Ch. 26



• RC Circuits
• equation derivation
• charging applet
• discharging applet
• Circuit simulator applet
Example #1
Example #2





• Practice:
  Try these additional examples
Example #3



• Prepare:
  Read textbook section 28-1 before the next lecture

POP5 21.59a
At steady state what is the voltage across the capacitor in the figure?
A. 2.00 V
B. 4.00 V
C. 6.00 V
D. 8.00 V
Answer

















POP5 21.59b
If the battery in the figure is disconnected, how much time does it take for ΔV_cap = 0.10ΔV₀?
A. 8.29 µs
B. 158 µs
C. 3.33 ms
D. 125 ms
Answer



















Walker5e 21.61
Two capacitors, C₁ = C and C₂ = 2C, are connected to a battery. Capacitor _____ stores more energy when they are connected to the battery in series and capacitor _____ stores more energy when they are connected in parallel with the battery.
A. C₁ ... C₁
B. C₂ ... C₁
C. C₁ ... C₂
D. C₂ ... C₂
Answer





































 



C. 6.00 V


The left side of the capacitor is at the higher potential.


















 



A. 8.29 µs




















 



C. C₁ ... C₂

When connected in series the two capacitors have the same charge. By noting that U = ½Q²/C you can see the smaller capacitor C₁ stores the most energy. (Confirm for yourself that if the battery voltage is 6.0 V and C = 10.0 µF, C₁ stores 80 µJ and C₂ stores 40 µJ.)
When connected in parallel the two capacitors have the same voltage. By noting that U = ½CV² you can see the larger capacitor C₂ stores the most energy. (Confirm for yourself that if the battery voltage is 6.0 V and C = 10.0 µF, C₁ stores 180 µJ and C₂ stores 360 µJ.)