Statement -1: A photodiode operates in revers | vedclass

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(A) photodiode is a special purpose $p-n$ junction diode fabricated with a transparent window to allow light to fall on the diode. It is operated unde

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Statement $-1$ is true,Statement $-2$ is true,Statement $-2$ is the correct explanation of Statement $-1$.

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(A) photodiode is a special purpose $p-n$ junction diode fabricated with a transparent window to allow light to fall on the diode. It is operated under reverse bias conditions.When the photodiode is illuminated with light (photons with energy $hu > E_g$),electron-hole pairs are generated near the depletion region. Due to the electric field of the depletion region,electrons and holes are separated before they can recombine. The direction of the electric field is such that electrons reach the $n$-side and holes reach the $p$-side,giving rise to an electric current.The reverse bias current in a $p-n$ junction is primarily due to minority charge carriers. The magnitude of this current is very small. When light falls on the junction,the number of minority carriers increases significantly,leading to a large fractional change in the reverse current. In contrast,the forward bias current is dominated by majority carriers,which are already present in large numbers. Therefore,the fractional change in forward current due to light is negligible and difficult to measure.Thus,Statement $-1$ is true,Statement $-2$ is true,and Statement $-2$ is the correct explanation of Statement $-1$.

Statement $-1$: $A$ photodiode operates in reverse bias.
Statement $-2$: The fractional change due to the photo-effects on the minority carrier dominated reverse bias current is more easily measurable than the fractional change in the forward bias current.

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Statement $-1$: $A$ photodiode operates in reverse bias.Statement $-2$: The fractional change due to the photo-effects on the minority carrier dominated reverse bias current is more easily measurable than the fractional change in the forward bias current.