Question

Capacitance of 3uf, 6uf, and 12uf are connected in series across a 350V supply.
Calculate 1: the equivalent circuit capacitance
2: the charge on each capacitor
3: the potential difference across each capacitor

Answer 1

1) So the equivalent capacity is $\frac{1}{C}=\frac{1}{C_1}+\frac{1}{C_2}+\frac{1}{C_3}=\frac{1}{3}+\frac{1}{6}+\frac{1}{12}=\frac{7}{12}$ , hence $C \approx1. 71 \mu F$

2) Since the charges on the capacitors are equal when connected in series, $U= \frac{q}{C}$

$q=U\times C=350\times 1.71= 598.5 \mu$$C$

3) $U_1=\frac{q}{C_1}=\frac{598.5 }{3}=199.5 V$

$U_2=\frac{598.5 }{6}=99.75 V$

$U_3=\frac{598.5 }{12}=49.875 V$