Question

(a) Calculate the value of $V_0$ and I if the Si diode and the Ge diode start conducting at $0.7V$ and $0.3V$ respectively, in the given circuit.
(b) If the Ge diode connection be reversed. What will be the new values of $V_0$ and I?

Answer 1

As in the given circuit,

Voltage,$V=12$V

Resistance,$R=5$k$\Omega$

$\therefore$, current,$I=\frac{12-0.3}{5k\Omega }=\frac{11.7V}{5\times {10}^3\Omega }=2.34$mA

Output voltage $V_0=RI=(5\times {10}^3)\times (2.34\times {10}^{-3})=11.7$V

When the connections of Ge diode are reversed, then current will bw through silicon.

In this case, current,$I=\frac{(12-0.7)V}{5\times {10}^{-3}\Omega }=2.26$mA

$\therefore$, Output voltage,$V_0=IR$

$=(2.26\times {10}^{-3})\times (5\times {10}^3)=11.3$V