23 - Capacitance Flashcards
1
Q
Define capacitance
A
the charge on the plates of the capacitor per unit potential difference across the plates
2
Q
Capacitance equation
A
C = Q/V
3
Q
Work done by charging a capacitor (3 equations)
A
W = 1/2QV
W = 1/2CV^2
W = 1/2Q^2/C
4
Q
Capacitors in parallel deriving
A
Q1 = C1V and Q2 = C2V
Q = Q1 + Q2 = C1V + C2V
Q = (C1+C2)V
C = C1 + C2 + C3 +…
5
Q
Capacitor in series deriving
A
V1 = Q/C1 and V2 = Q/C2
V = Q/Ctotal
V = V1 + V2
1/Ctotal = 1/C1 + 1/C2 + 1/C3 + …
6
Q
Time constant for a capacitor discharging (equation)
A
t = RC
