(N/A) The necessity of combining capacitors arises when we need a specific value of capacitance that is not available in a single capacitor. By combining capacitors,we can achieve a desired equivalent capacitance.
There are two primary ways to connect capacitors:
$(1)$ Series combination: In this arrangement,capacitors are connected end-to-end. The equivalent capacitance $C_{eq}$ is given by $\frac{1}{C_{eq}} = \frac{1}{C_1} + \frac{1}{C_2} + \dots + \frac{1}{C_n}$. This combination is used to decrease the total capacitance.
$(2)$ Parallel combination: In this arrangement,all capacitors are connected across the same potential difference. The equivalent capacitance $C_{eq}$ is given by $C_{eq} = C_1 + C_2 + \dots + C_n$. This combination is used to increase the total capacitance.