Circuits with resistors:
Note: Replacing resistors in parallel with one resistor of equivalent total resistance is very useful when analyzing circuits
Circuits with capacitors:
Q=Q1=Q2=Q3=Q4=... (Conservation of charge)
Q=Q1+Q2+Q3+Q4... (Conservation of energy)
After a long time, a capacitor acts like an open spot in the circuit; current through the section of the circuit with the capacitor= 0 A
Time constant=RC, or Greek letter tau
When a resistor and capacitor are in parallel, voltage drop across resistor=voltage drop across capacitor.
When a resistor and capacitor are in series, current is the same through the resistor as through the capacitor.
Charging RC Circuit: Current decreases over time. Charge on capacitor and potential drop across capacitor increase over time.
*In the long run,VC=VT (V-terminal=V-capacitor)
Discharging a capacitor: Current flows from the positive plate of capacitor to the negative plate and through the resistor. Current, charge, and voltage decrease over time.