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Semiconductor System Lab

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Question on Diode and Resistor in Series

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작성자 김준하 댓글 1건 조회 736회 작성일 20-04-08 00:07

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Hello, I have a question about the following image from the textbook on page 91.

Since there is a voltage drop due to the resistor, shouldn't the diode (D1) turn on when V_in exceeds V_R + V_B1 + V_D,on ?
It seems like all of the other questions/examples from the textbook ignore the voltage drop due to the resistor, and I don't quite understand the reason for it.

Thank you.

(I have attached the example figure below).

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TA님의 댓글

TA 작성일

It seems that the question assumes an ideal diode.
When the Vin is within [-Vdon - Vb2, Vdon + Vb1],
both diodes D1 and D2 are off so the current is 0.
When the Vin is Vdon + Vb1, diode D1 is almost on and the current is almost zero.
Therefore, you can ignore the voltage drop in this case so the Vout is same as Vin.

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