The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because: (a) fractional change in majority carriers produce higher forward bias current (b) fractional change in majority carriers produce higher reverse bias current (c) fractional change in minority carriers produce higher forward bias current (d) fractional change in minority carriers produce higher reverse bias current

Answer: (d). Light creates electron-hole pairs; this changes the minority carrier concentration a lot (in fraction) but majority carriers only slightly. Reverse current is carried by minority carriers, so the fractional change in reverse current is large and easy to measure. So the answer is (d) fractional change in minority carriers produces higher reverse bias current.

The photodiode is used to detect the optical signals. These diodes… | JEE Main 2022 (25 Jun, Shift 1)

Q57JEE Main 2022 · 25 JUN · SHIFT 1Medium

Special Purpose Diodes

The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because:

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Answer: (d)

Light creates electron-hole pairs; this changes the minority carrier concentration a lot (in fraction) but majority carriers only slightly.
Reverse current is carried by minority carriers, so the fractional change in reverse current is large and easy to measure.
So the answer is (d) fractional change in minority carriers produces higher reverse bias current.

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