Capacitors in  Series 

apacitors are said to be connected together "in series" when they are effectively "daisy chained" together in a single line. The charging current (ic) flowing through the capacitors is THE SAME for all capacitors as it only has one path to follow and iT = i1 = i2 = i3 etc. Then, Capacitors in Series all have the same current so each capacitor stores the same amount of charge regardless of its capacitance. This is because the charge stored by a plate of any one capacitor must have come from the plate of its adjacent capacitor therefore,

QT = Q1 = Q2 = Q3 ....etc

In the following circuit, capacitors, C1C2   and C3  are all connected together in a series branch between points A and B

Capacitors in series 

In the previous parallel circuit we saw that the total capacitance, CT of the circuit was equal to the sum of all the individual capacitors added together. In a series connected circuit however, the total or equivalent capacitance CT is calculated differently. The voltage drop across each capacitor will be different depending upon the values of the individual capacitances. The voltage from point A to point B has to equal the sum of the voltages across the capacitors.

Since Q = CV or V = Q/C, substituting Q/C for each capacitor voltage VC in the above KVL equation gives us

dividing each term through by Q gives

Example Problem 

Definition provided by Electronic tutorials