Match oscillator types to their characteristic features: (A) Wien Bridge, (B) Colpitt’s, (C) Hartley, (D) Clapp — with (1) RF oscillator using two inductors and one capacitor, (2) RF oscillator using three capacitances and one inductance, (3) RC oscillator for audio frequencies, (4) RF oscillator using two capacitances and one inductance.

Introduction:
Oscillator categorization hinges on the frequency-determining network. Recognizing RC vs LC topologies and how inductors/capacitors are arranged is critical for selecting an appropriate oscillator for audio or RF applications.

Given Data / Assumptions:

• Wien Bridge: bridge-type RC network, low distortion, audio-range.
• Colpitt’s: LC with capacitive divider (two capacitors, one inductor).
• Hartley: LC with inductive divider (two inductors or tapped inductor, one capacitor).
• Clapp: modified Colpitt’s with an additional series capacitor improving frequency stability.

Concept / Approach:

RC oscillators (e.g., Wien Bridge) dominate audio/low-frequency generation. LC oscillators (Colpitt’s, Hartley, Clapp) target RF. The component split (capacitive vs inductive division) distinguishes Colpitt’s and Hartley; Clapp introduces a third capacitance in series to refine stability and reduce dependence on transistor/internal capacitances.

Step-by-Step Solution:

Verification / Alternative check:

Standard oscillator tables list these associations; frequency equations confirm RC vs LC dependencies.

Why Other Options Are Wrong:

Swapping Colpitt’s and Hartley confuses divider type; assigning Wien Bridge to RF ignores its RC nature.

Common Pitfalls:

Assuming any LC is interchangeable; overlooking Clapp’s extra series capacitor and its benefit to frequency stability.

Final Answer:

A-3, B-4, C-1, D-2