Tuned amplifiers — series vs parallel LC usage: In RF/mid-frequency tuned amplifier stages, are parallel (tank) LC resonators used more commonly for selectivity and impedance transformation than series LC combinations?

Introduction / Context:
Tuned amplifiers rely on resonant networks to select narrow frequency bands and to provide impedance matching. Two fundamental LC forms exist: series resonators (low impedance at resonance) and parallel resonators (high impedance at resonance). Understanding which is more common in amplifier input/output stages is important for practical RF design.

Given Data / Assumptions:

• Discrete or integrated tuned stages in radio/IF/RF amplifiers.
• Desire for band-selective loading and impedance transformation.
• Use of passive, linear LC networks.

Concept / Approach:
A parallel LC at resonance presents a high impedance (tank), favoring voltage gain, selectivity, and isolation between stages. It can be tapped or transformer-coupled for impedance matching. Series LC resonates to a low impedance and is often used for coupling, notch/series traps, or as part of impedance-matching networks, but not as commonly as the main tuned load in amplifiers.

Step-by-Step Solution:

Verification / Alternative check:
Examine classic tuned-collector or tuned-drain stages and double-tuned IF transformers; these use parallel LC tanks as resonant loads with transformer coupling for bandwidth shaping.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing impedance behavior of series versus parallel resonance; overlooking that the choice depends on whether a high- or low-impedance condition at resonance is desired.

Final Answer:
Yes — parallel LC tanks are more commonly used