Special Purpose Diodes
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Photodiodes are preferably operated in reverse bias condition for light intensity measurement.
Reason R: The current in the forward bias is more than the current in the reverse bias for a junction diode.
In the light of the above statements, choose the correct answer from the options given below:
Show answer and solution
Answer: (d)
- A: in reverse bias the photocurrent (from minority carriers) is a large fraction of the small reverse current, so intensity changes are easy to measure. A is true.
- R: forward current is indeed larger than reverse current, so R is true.
- But R does not explain why reverse bias is preferred; the reason is the fractional change in reverse current.
- So the answer is (d) both true, R is not the correct explanation.