Compared with carbon composition resistors, what is one key advantage of carbon film resistors in low-noise or precision-biased circuits?

Introduction / Context:
Choosing resistor technology impacts noise, stability, and tolerance. Carbon composition (bulk carbon) and carbon film (deposited carbon on ceramic) are two legacy technologies with distinct characteristics important in audio, sensor biasing, and analog front-ends.

Given Data / Assumptions:

• Comparison is between carbon composition and carbon film.
• Noise and tolerance are primary concerns.

Concept / Approach:
Carbon composition resistors exhibit higher excess noise and wider tolerance due to granular conductive paths. Carbon film parts, produced via deposited film and laser trimming, generally have lower excess noise and better tolerance for the same value and size, making them preferable for low-level analog signals.

Step-by-Step Solution:
Identify performance metric: noise in microvolt-level circuits.Compare technologies: carbon film typically shows lower excess noise index.Conclude: carbon film offers less circuit noise than carbon composition.

Verification / Alternative check:
Manufacturer datasheets and application notes report improved noise and tighter tolerance (e.g., ±1%–±5%) for carbon film versus typical ±5%–±20% for carbon composition parts.

Why Other Options Are Wrong:

• Smaller size / higher wattage: Size and wattage vary by series; not an inherent carbon film advantage over composition.
• Poor tolerance: Carbon film usually has better tolerance than composition.

Common Pitfalls:

• Selecting composition parts for sensitive analog stages due to availability, then chasing unexplained hiss or drift.
• Overlooking environmental stability; film types typically age better.

Final Answer:
less circuit noise