Question

In the following figure, the diodes which are forward biased, are :-

• A. (a), (b) and (d)
• B. (c) only
• C. (a) and (c)
• D. (b) and (d)

Answer 1

None of the options are correct

Answer 2

To determine if a diode is forward biased, we compare the potential at its p-type (anode) terminal with the potential at its n-type (cathode) terminal. A diode is forward biased if the potential at the p-type terminal ($V_p$) is greater than the potential at the n-type terminal ($V_n$), i.e., $V_p > V_n$.

Let's analyze each case:

Case (a):

• The p-type terminal is at +5 V.
• The n-type terminal is connected to +10 V.
• $V_p = +5 \text{ V}$
• $V_n = +10 \text{ V}$
• Since $V_p < V_n$ (+5 V < +10 V), the diode is reverse biased.

Case (b):

• The p-type terminal is at -10 V.
• The n-type terminal is connected to ground (0 V).
• $V_p = -10 \text{ V}$
• $V_n = 0 \text{ V}$
• Since $V_p < V_n$ (-10 V < 0 V), the diode is reverse biased.

Case (c):

• The p-type terminal is at -12 V.
• The n-type terminal is connected to -5 V.
• $V_p = -12 \text{ V}$
• $V_n = -5 \text{ V}$
• Since $V_p < V_n$ (-12 V < -5 V), the diode is reverse biased.

Case (d):

• The p-type terminal is connected to ground (0 V).
• The n-type terminal is connected to +5 V.
• $V_p = 0 \text{ V}$
• $V_n = +5 \text{ V}$
• Since $V_p < V_n$ (0 V < +5 V), the diode is reverse biased.

Based on the standard definition of forward biasing, none of the diodes are forward biased. All of them are reverse biased. The question appears to be flawed, as none of the provided options are correct.