Quadrant claim for Class B chopper Evaluate the statement: “A Class B chopper operates in the third quadrant.” Determine whether it is correct and justify based on voltage and current polarities.

Introduction / Context:
Chopper classes are assigned by the voltage and current signs at the DC output. This determines the quadrant of operation and the direction of power flow (to the load or back to the source).

Given Data / Assumptions:

• Class B chopper is a regenerative step-up type.
• Voltage reference is positive at the load; current positive into the load.

Concept / Approach:
Quadrants: Q1 (+V, +I), Q2 (+V, −I), Q3 (−V, −I), Q4 (−V, +I). Class B returns energy from the load to the source with a positive load voltage and negative current (current flowing from load to source), which is Quadrant II.

Step-by-Step Solution:
Identify Class B behavior → regeneration with V > 0 and I < 0.Match to quadrant → Q2, not Q3.Therefore, the statement “operates in third quadrant” is incorrect.

Verification / Alternative check:
Energy sign: P = V*I is negative for Class B, consistent with power flowing back to the source, and with Q2 coordinates.

Why Other Options Are Wrong:
Marking it True would imply V < 0, I < 0 (Q3), which is not the case for standard Class B implementations.

Common Pitfalls:
Mixing up Class B (single-quadrant regeneration in Q2) with multi-quadrant choppers (Class C or D) that can access Q3 in specific configurations.

Final Answer:
False