Capacitors in parallel – Compare equivalent to individual values Statement: “Total parallel capacitance is less than that of the smallest capacitor in parallel.” Determine correctness.

Difficulty: Easy

Correct Answer: False

Explanation:


Introduction / Context:
Knowing how capacitors combine is essential for filter design, decoupling, and tuning networks. Parallel and series combinations behave oppositely, and mixing them up leads to large design errors.



Given Data / Assumptions:

  • Ideal capacitors without significant parasitic inductance or resistance.
  • Capacitors connected strictly in parallel across the same two nodes.
  • Capacitance values are positive and finite.


Concept / Approach:

For capacitors in parallel, capacitances add: C_eq = C1 + C2 + ... + Cn. Therefore, the equivalent is greater than each individual capacitor and certainly greater than the smallest one. The given statement claims the opposite and is incorrect.



Step-by-Step Solution:

Write the rule: C_eq,parallel = Σ Ci.Compare C_eq to any Ci: since all Ci > 0, C_eq > max{Ci} ≥ min{Ci}.Therefore, C_eq cannot be less than the smallest capacitor.


Verification / Alternative check:

Energy perspective: for a given voltage V, stored energy in the bank is (1/2) * C_eq * V^2, which increases as more capacitors are added in parallel, confirming the additive behavior.



Why Other Options Are Wrong:

Invoking dielectric type, frequency, or plate area does not reverse the ideal rule; parasitics may alter high-frequency impedance but not the DC/low-frequency capacitance sum in true parallel.



Common Pitfalls:

Confusing series and parallel rules: series reduces overall capacitance (below the smallest value), while parallel increases it (above the largest value).



Final Answer:

False.

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