Real-world modeling: A practical capacitor is not ideal. Which simple equivalent model best represents its behavior for DC leakage and AC response in many applications?

Introduction:
Ideal capacitors block DC and pass AC according to reactance, but practical devices also exhibit leakage and losses. This question targets the most common first-order model used in circuit analysis and datasheets.

Given Data / Assumptions:

• Focus on a simple, low-order equivalent.
• Consider DC leakage and basic AC behavior.
• Ignore series inductance and ESR for this introductory model.

Concept / Approach:
A practical capacitor can be modeled as an ideal capacitor in parallel with a large resistor (leakage path). More detailed models add ESR in series and ESL, but the parallel resistor captures finite insulation resistance and DC leakage.

Step-by-Step Solution:
1) Identify leakage: real dielectrics allow tiny DC current.2) Represent leakage with a high-value resistor in parallel.3) Retain ideal C element to represent energy storage in the electric field.4) Recognize that ESR and ESL are refinements for high-frequency work.

Verification / Alternative check:
Datasheets specify insulation resistance or leakage current, which maps directly to a parallel resistance model at rated conditions.

Why Other Options Are Wrong:
Is a short to DC: false; capacitors block DC ideally and leak only slightly.Is an open to AC: false; capacitive reactance allows AC current.Stores energy in a magnetic field: that describes inductors; capacitors store energy in an electric field.

Common Pitfalls:
Assuming ideal behavior and ignoring leakage can cause bias drift and timing errors in precision circuits.

Final Answer:
Looks like a capacitor in parallel with a resistor