Friday, May 1, 2015

Capacitor in Series and Parallel; Parallel Capacitors; Series Capacitors

We have seen that in the resistances in the case of a series connection their ohmic value increases, while in the case of a parallel connection decreases.

To know about series and Parallel connection in case of resistor please visit:-

In capacitors is the exact opposite:-

Series connections of capacitors:-
A series of two capacitors will reduce their net capacitance which is similar to if distance between capacitor plates is increased, but working voltage will increase. In series connections charge stored by each capacitor is same. If we apply a voltage source to series connected capacitors than current flow will have only one path which will leads to same voltage across each capacitor.

Parallel Connections of Capacitors
In the case of a parallel connection the capacitors will have a higher capacity which is similar to as if they increased the size of the two plates, remain unchanged by their working voltage.

So let's see how they are calculated these two aspects will arise .

Capacitors in series: 
the value of the capacity that we will get if we will connect two capacitors in series will always be less than the capacity smaller. For example, if C1 had a capacity of 100 nF and C2 of 10nF, the final capacity will be certainly lower than 10nF.

Capacitor in Series

The formula to derive the final capacity of a series is: (C1xC2) :( C1 + C2), in consequence Ctot = (100x10) :( 100 + 10) = 9.09nF.
If for example in our circuit there were n capacitors, the formula to derive the total capacity is transformed into: 1: 1 + C1: C2 + ... 1: RCN;
This is a formula obtained only to speed up operations in the design phase.

Capacitors in parallel:
The value that will get in the case of a parallel connection, will always be greater than each individual capacitive value. It 'easy to understand why if we keep this formula: Ctot = C3 + C4, therefore 100 + 10 = 110nF. Accordingly, to derive the total capacity of n condenzatori it will use the formula: C3 + C4 + ... Cn.

Capacitor in Parallel

SI prefixes of capacitive values:


picofarad: 1,000 = nanofarad
picofarad: 1,000,000 = microfarads

nanofarad: = 1.000 microfarads
nanofarad x 1,000 = picofarad

x = 1.000 microfarads nanofarad
microfarads x 1,000,000 = picofarad

Note1: the formulas described above are valid for all types of capacitors, even if for the electrolytic must respect their polarities. In the case of series connection the positive pole must be connected with the negative pole of the second capacitor, while in the case of a parallel connection, the two positive poles must be connected together, same thing for the negative poles.

Note 2: in the capacitors is very important to the working voltage (is always printed on its wrapping after the capacity). For example, if collaghiamo a capacitor of 16V 100mF the heads of a voltage of 24V, it will damage in a matter of seconds; It is always better to choose a capacitor voltage higher than the required, in this case one from 100mF 35V would do fine.

Electrical Power in Series and Parallel