Ge and Si diode conduct at 0.3 V and 0.7respectively . In the following figure if Ge diode connection is reversed, the value of `V_0` changes by

Options

A. 0.2 V
B. 0.4 V
C. 0.6 V
D. 0.8 V

Answer

B

Explanation

Consider the case when Ge and Si diodes are connected
Equivalent voltage drop cross the combination Ge and Si diode = 0.3 V
`implies ` Current `i=(12-0.3)/(5kOmega)=2.34mA`
`:.` Output voltage `V_0 =Ri = 5kOmega xx 2.34 mA = 11.7V`
Now consider the case when diode connection are reversed. In this case voltage drop across the diode.s combination = 0.7 V
`implies ` Current `i=(12-0.7)/(5kOmega) = 2.26mA`
`:. V_0=iR=2.26mA xx5kOmega =11.3 V`
Hence charge in the value of `V_0=11.7-11.3 = 0.4V`