Question

$Ge$ and $Si$ diodes start conducting at $0.3 \,V$ and $0.7\, V$ respectively. In the following figure if Ge diode connection are reversed, the value of $V_o$ changes by : (assume that the Ge diode has large breakdown voltage)

• A. $0.6\, V$
• B. $0.8\, V$
• C. $0.4 \,V$
• D. $0.2 \,V$

Answer 1

Answer: (C)

$0.4 \,V$

Answer 2

Initially $Ge$ & $Si$ are both forward biased so current will effectivily pass through $Ge$ diode with a drop of $0.3\, V$
if $''Ge''$ is revesed then current will flow through $''Si''$ diode hence an effective drop of $(0.7 - 0.3) = 0.4\, V$ is observed.