Notes
$$C=\frac{Q}{\Delta V},\quad C_{parallel\,plate}=\frac{\varepsilon_0A}{d},\quad U=\frac{1}{2}C(\Delta V)^2$$
- Parallel: $C_{eq}=C_1+C_2$. Series: $\displaystyle \frac{1}{C_{eq}}=\frac{1}{C_1}+\frac{1}{C_2}$.
Practice
Two 4 μF capacitors in series. $C_{eq}=$
Like resistors in parallel.
Doubling the plate area makes $C$:
$C\propto A$.
A capacitor disconnected from the battery has its plates pulled apart. $Q$:
Charge can't leave.
Ready for more? Take the Unit 10 test.