There are 7 capacitors, equivalent capacitance in series is C, then what will the equivalent capacitance in parallel
Answers
Answer:
Explanation:The voltage ( Vc ) connected across all the capacitors that are connected in parallel is THE SAME. Then, Capacitors in Parallel have a “common voltage” supply across them giving:
VC1 = VC2 = VC3 = VAB = 12V
In the following circuit the capacitors, C1, C2 and C3 are all connected together in a parallel branch between points A and B as shown.
capacitors in parallel
When capacitors are connected together in parallel the total or equivalent capacitance, CT in the circuit is equal to the sum of all the individual capacitors added together. This is because the top plate of capacitor, C1 is connected to the top plate of C2 which is connected to the top plate of C3 and so on.
The same is also true of the capacitors bottom plates. Then it is the same as if the three sets of plates were touching each other and equal to one large single plate thereby increasing the effective plate area in m2.
Since capacitance, C is related to plate area ( C = ε(A/d) ) the capacitance value of the combination will also increase. Then the total capacitance value of the capacitors connected together in parallel is actually calculated by adding the plate area together. In other words, the total capacitance is equal to the sum of all the individual capacitance’s in parallel. You may have noticed that the total capacitance of parallel capacitors is found in the same way as the total resistance of series resistors.
The currents flowing through each capacitor and as we saw in the previous tutorial are related to the voltage. Then by applying Kirchoff’s Current Law, ( KCL ) to the above circuit, we have
Total Circuit Current
and this can be re-written as:
total circuit capacitance
Then we can define the total or equivalent circuit capacitance, CT as being the sum of all the individual capacitance’s add together giving us the generalized equation of:
Parallel Capacitors Equation
capacitors in parallel equation
When adding together capacitors in parallel, they must all be converted to the same capacitance units, whether it is μF, nF or pF. Also, we can see that the current flowing through the total capacitance value, CT is the same as the total circuit current, iT
We can also define the total capacitance of the parallel circuit from the total stored coulomb charge using the Q = CV equation for charge on a capacitors plates. The total charge QT stored on all the plates equals the sum of the individual stored charges on each capacitor therefore,
Equivalent Capacitance in Parallel
As the voltage, ( V ) is common for parallel connected capacitors, we can divide both sides of the above equation through by the voltage leaving just the capacitance and by simply adding together the value of the individual capacitances gives the total capacitance, CT. Also, this equation is not dependent upon the number of Capacitors in Parallel in the branch, and can therefore be generalized for any number of N parallel capacitors connected together.