Electronics and Communication Engineering - Analog Electronics - Discussion

Discussion Forum : Analog Electronics - Section 1 (Q.No. 7)
7.
In figure v1 = 8 V and v2 = 4 V. Which diode will conduct?
D2 only
D1 only
Both D1 and D2
Neither D1 nor D2
Answer: Option
Explanation:

D1 will conduct and the output voltage will be about 7 V. Therefore D2 will be reverse biased and will not conduct.

Discussion:
32 comments Page 4 of 4.

Aatif Khan said:   4 years ago
Option B is correct.

First, consider both the diodes forward bias.
Then with the help of nodal analysis find the voltage at junction 1k,1k and 10k.

{((V-8)/1k) +((V-4)/1k)+(V/10k)} = 0.
On solving the above equation we get, V = 5.71v.

Given that V1=8v and V2=4v which are positive terminal voltage for D1 and D2 respectively
for both diodes, we have a negative terminal voltage V=5.71v.

So D1 will conduct because Vp>Vn (condition for forwarding bias) (Vp=8v, Vn=5.71v)
D2 will not conduct because Vp<Vn (condition for reverse bias) (Vp=4v, Vn=5.71v).
(6)

Sandhya said:   4 years ago
Thank you @Aatif.
(1)


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