Updated: Dec 9, 2025 | Source: 2024-2028 Question Pool | Topic: E5D
E5D08E5D

What is the primary cause of loss in film capacitors at RF?

Deep Dive: E5D08

The correct answer is D: Skin effect. What is the primary cause of loss in film capacitors at RF is skin effect. Skin effect in the capacitor's electrodes causes loss at RF. For amateur radio operators, this is important for understanding capacitor losses. Understanding this helps when selecting capacitors.

Why Other Answers Are Wrong

Option A (Inductance): Incorrect. Inductance isn't the primary cause of loss - skin effect is. Inductance isn't the primary cause. Option B (Dielectric loss): Incorrect. Dielectric loss isn't the primary cause at RF - skin effect is. Dielectric loss isn't the primary cause. Option C (Self-discharge): Incorrect. Self-discharge isn't the primary cause of loss - skin effect is. Self-discharge isn't the primary cause.

Exam Tip

Film capacitor loss at RF = skin effect primary cause. Think 'F'ilm 'C'apacitor 'L'oss = 'S'kin 'E'ffect. Skin effect in the capacitor's electrodes causes loss at RF. Not inductance, not dielectric loss, not self-discharge - just skin effect.

Memory Aid

Film capacitor loss at RF = skin effect primary cause. Think 'F'ilm 'C'apacitor = 'S'kin 'E'ffect loss. Skin effect in the capacitor's electrodes causes loss at RF. Important for understanding capacitor losses.

Real-World Example

Film capacitors at RF: The primary cause of loss is skin effect. At RF frequencies, skin effect in the capacitor's metal electrodes increases resistance and causes loss. This is the primary cause - skin effect.

Source & Coverage

Question Pool: 2024-2028 Question Pool

Subelement: E5D

Reference: 2024-2028 Question Pool · E5 - Electrical Principles

Key Concepts

Primary cause of loss Film capacitors at RF Skin effect Capacitor losses

Verified Content

Question from the official FCC Extra Class pool. Explanation reviewed by licensed amateur radio operators and mapped to the E5D topic.