NEET 2025 physics semiconductor devices full wave rectifier question

 This tutorial provides a detailed walkthrough of a NEET 2025 physics problem from the Semiconductor Devices chapter, focusing specifically on the operation of a Full-Wave Rectifier circuit.

Core Concepts Covered:

The video explains the behavior of diodes  in a center-tapped full-wave rectifier system:

  • Circuit Analysis: The problem features an input supply voltage V_{in} = 220 \sin(100 \pi t) and asks to determine the state of the diodes at a specific time, t = 15 ms.

  • Frequency & Time Period: The instructor demonstrates how to calculate the time period (T) of the AC supply from the given angular frequency (omega = 100 \pi).

  • Diode Biasing:

    • During the first half-cycle (0 to 10 ms), one diode is forward-biased while the other is reverse-biased.

    • At t = 15 ms, which falls within the second half-cycle (10 to 20 ms), the polarity of the secondary transformer reverses.

    • Consequently, D_2 becomes forward-biased (conducting), while D_1 becomes reverse-biased (non-conducting) [02:17].

Key Takeaways for Students:

  • Identify the Phase: Learn to determine which part of the AC cycle the circuit is in by comparing the given time (t) to the calculated time period (T).

  • Role of the Center Tap: Understand how the center-tapped transformer provides out-of-phase voltages to the two diodes, allowing for full-wave rectification [03:07].

  • Quick Exam Strategy: The video highlights how to quickly eliminate incorrect options by focusing on the half-cycle logic.



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