The Series And Parallel Capacitors Formula To Calculate The Right Capacitances


The series and parallel combination of capacitors is important in the electronic repair line. Not every capacitor value you can find from the electronic suppliers thus you have to use the series and parallel capacitor formula to calculate your desire capacitor value and voltage rating for replacement. It is quite simple to find a replacemnt with the formula given below



Capacitor In Series

series capacitor

If two or more capacitors are connected in series as shown above, the total capacitance is less than that of the smallest capacitor in the group.The value of the total capacitance C can be calculated by the formula below. The results is exactly the same as the resistances in parallel. If the capacitors of 1 microfarad each are connected in series, the net capacitance value offered by the combination of the two capacitors is: -


series capacitors

So the net value is just half of an individual capacitor. Capacitors are used in series to provide a higher voltage breakdown rating for the combination. In many circuits,high value resistors are connected in parallel with all capacitors to ensure that the voltage is distributed equally. These resistors should have enough wattage rating to dissipate heat generated by the flow of current through them.

When electrolytic capacitors are to be connected in series, connect the positive side of the capacitor to negative exactly as when you are connecting batteries in series. (Fig. 1)


series capacitance

In series capacitors, the working voltage of each capacitor is sum up. This series connection decreased the capacitance but an increase in working voltage.


series capacitances


The total value of this combination is: -


parallel capacitor


but the working voltage becomes 700 volt.

Capacitors in Parallel

When a number of capacitors are connected in parallel as shown below, the total or effective capacitance of the group is equal to the sum of the individual capacitancesThe equation for calculating the total capacitance C obtained by capacitances C1, C2 C3 etc.The formula for parallel capacitor is same as the resistance in series.

parallel capacitors

If 5, 10 and 15 microfarad capacitors are connected in parallel as shown below, the combination would provide a total value capacitance of 30 microfarad. This type of connection is used to get higher capacitances. The voltage rating of each capacitor should be sufficient to withstand the voltage that will be applied to them in practical circuits.

 parallel capacitance

When electrolytic capacitors are connected in parallel, make sure the capacitor polarity connect from positive to positive and negative to negative otherwise the capacitor may not work or blow.

parallel capacitances

The working voltage of parallel capacitors is equal to the lowest working voltage rating in the combination. For example, the total value capacitance of the combination is:-

CT = C1 + C2 + C3


series capacitor voltage

CT = 1µF + 2µF + 1µF = 4µF

and working voltage = 100 volt

Series and parallel capacitors formula is a good way to find a capacitance value for replacement. Use a digital capacitance meter and test all the results you have connected the capacitors either in series or in parallel.