Calculating Capacitance in Series & Parallel (Cambridge (CIE) A Level Physics): Revision Note
Exam code: 9702
Calculating capacitance in series and parallel
Like resistors, capacitors can be combined in series and parallel
Often, circuits may contain combinations of capacitors in both series and parallel arrangements
In a series arrangement:
the reciprocal of the combined capacitance is equal to the sum of the reciprocals of the individual capacitances
the combined capacitance of two identical capacitors is equal to half of the value of each one
the combined capacitance is always less than the value of the smallest individual capacitance
In a parallel arrangement:
the combined capacitance is equal to the sum of all the individual capacitances
the combined capacitance of two identical capacitors is equal to twice the value of each one
the combined capacitance is always greater than the value of the any individual capacitance
Worked Example
Three capacitors with capacitance of 23 μF, 35 μF and 40 μF are connected as shown below.
Calculate the total capacitance between points A and B.
Answer:
Step 1: Calculate the combined capacitance of the two capacitors in parallel
To calculate capacitance in parallel:
Ctotal = C1 + C2 + C3 …
Cparallel = 23 + 35 = 58 μF
Step 2: Connect this combined capacitance with the final capacitor in series
To calculate capacitance in series:
Step 3: Rearrange for the total capacitance
Unlock more, it's free!
Join the 100,000+ Students that ❤️ Save My Exams
the (exam) results speak for themselves:
Was this revision note helpful?
Build on this topic
