If the capacitors are electrolytic capacitor, extra care should be taken with the polarity. The + wire of the first capacitor must be connected to the - wire of the next one, like when connecting batteries in series: When connecting capacitors in series, the total capacitance is calculated from the following series:
There are both advantages and disadvantages to connecting capacitors in series together. On the plus side, the voltage rating of the series connection increases, allowing the circuit to handle higher voltage levels without risking damage to the capacitors. This feature is particularly useful in high-voltage capacitors in series applications.
Combining capacitors in series reduces the total capacitance, and isn't very common, but what are some possible uses for it? It shouldn't be used to increase the voltage rating, for instance, since you can't guarantee that the middle will be at half the DC voltage of the total, without using bleeder resistors.
Here, also, we can easily see that once we connect the capacitors in series connection, then the resulting capacitance becomes smaller than the smallest capacitance in the combination. In other words, the total capacitance of the circuit decreases once we connect the capacitors in series form.
Thus, if you need to have a capacitor in a high voltage circuit it may be necessary, or just more convenient, to place them in series. Recovering the nominal capacitance of the individual capacitor, if needed, is a question of building up an array of them in parallel.
The more the capacitors in a series connection, the less the total capacitance becomes. Thus, the more the capacitors in a series connection, the more the impedance of the series. Same as when connecting resistors in series, the sum of voltage drops across each capacitor equals to the voltage across the whole series: