Question

The delay time can be reduced by?

(a) decreasing lifetime and increasing ratio of reverse to forward current

(b) increasing lifetime and decreasing ratio of reverse to forward current

(c) increasing lifetime and increasing ratio of reverse to forward current

(d) decreasing lifetime and decreasing ratio of reverse to forward current

I have been asked this question in my homework.

Enquiry is from PN Diode Switching Times topic in portion Semiconductor-Diode Characteristics of Electronic Devices & Circuits

Answer 1

Right choice is (a) decreasing lifetime and increasing ratio of reverse to forward current

To elaborate: When the current increases the depletion layer decreases and the storage and transition time decreases. A decreased depletion layer can easily discharge the excess carrier and thereby lessens the delay time.