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InterviewSolution
| 1. |
How is it that the reverse current in Zener diode starts increasing suddenly at a relatively low breakdown voltage of 5 volt or so ? |
| Answer» Solution :Zener diode is fabricated by HEAVILY doping both p- and n-sides of the p-n junction. As a result, the depletion REGION formed is very THIN, even less than `10^(6)` m, and consequently the electric field at the junction is extremely high (of the order of `5 XX 10^(6)` V/m or even more) even for a small REVERSE bias voltage of about 5 V and breakdown voltage has a low value of about 5 V. When the reverse bias voltage is equal to Zener (or breakdown) voltage `["i.e., "V_(R) ge V_(Z) ]` ,the electric field is high enoughto pull valence electrons from the host atoms on p-side of the junction, which are then accelerated to n-side . These electrons account for high current observed at the breakdown stage. | |