Question

Which of the following circuits is reverse-biased?

• A.
• B.

  

• C.

  

• D.

  

Answer 1

The Correct Option is D

To determine which of the circuits is reverse-biased, we need to understand what reverse biasing means in the context of a diode within a circuit.

• A diode is said to be reverse-biased when the voltage at the cathode (negative side) is higher than the voltage at the anode (positive side). This prevents the current from flowing through the diode.
• In contrast, a diode is forward-biased when the voltage at the anode is higher than at the cathode, allowing current to flow.

From the analysis, Circuit 4 is the only circuit where the diode is reverse-biased. Hence, the correct answer is:

This solution is based on the fundamental principles of diode operation concerning forward and reverse biasing. In a reverse-biased condition, current does not flow due to the orientation of the voltage across the diode.

Answer 2

In a diode circuit, for the diode to be forward-biased, the P-end should be connected to a higher potential than the N-end. In option (4), the P-end of the diode is connected to the negative terminal of the power supply, while the N-end is connected to the positive terminal. This configuration causes the diode to be reverse-biased, as it is in opposition to the direction required for forward bias.
Thus the correct answer is option 4.