Question

Of the diodes shown in the following diagrams, which one of the diode is reverse biased ?

• A.
• B.
• C.
• D.

Answer 1

The Correct Option is D

To determine which diode is reverse biased, we need to understand the basic working principle of a diode. A diode allows current to flow primarily in one direction (forward-biased) while blocking it in the opposite direction (reverse-biased). In a forward-biased diode, the anode is connected to a higher potential than the cathode. In a reverse-biased diode, the cathode is at a higher potential than the anode.

Let's examine each option:

1. 

   In this option, the diode is forward-biased because the anode (left side of the diode symbol) is at a higher potential than the cathode (right side).

2. 

   In this option, the diode is also forward-biased as the anode is connected to a higher potential than the cathode.

3. 

   This diagram also shows a forward-biased diode with the anode at a higher potential compared to the cathode.

4. 

   This option shows a reverse-biased diode, where the cathode (right side of the diode symbol) is at a higher potential than the anode. Thus, this diode is reverse biased and will not conduct current under standard operating conditions.

From the analysis above, the correct diagram showing a reverse-biased diode is:

When answering exam questions related to diodes, always check the potential difference between the anode and the cathode. A higher potential at the cathode means the diode is reverse-biased, while a higher potential at the anode means it is forward-biased.