Question

Consider the diode circuit shown in the figure below:


The input output characteristic curve of the circuit can be represented as
(Assume cut-in voltage of diode $D_1$ and $D_2$ is equal to 0.7 V)

• A.
• B.
• C.
• D.

Answer 1

The correct option is C

Case I : $\text{For}-0.7V<V_{\text{in}}<$5.7~V
Both Diode $D_1$ and $D_2$ will be OFF and output will be equal to zero.

Case II : $\text{For}{V}_{\text{in}}>5.7V$
Diode $D_2=ON\text{and}{D}_1=$ OFF, thus the circuit can be redrawn as





thus, $V_{\text{in}}=V_{\text{out}}+5.7V,$ hence slope = 1 (for values of output voltages greater than 5.7 V)

Case III : When $V_{\text{in}}<-0.7V$
Then $D_1$ will be ON and $D_2=OFF$

Hence, the circuit will be redrawn as




$\text{hence,}{V}_0=V_{\text{in}}\times \frac{1}{2}-0.7V$
Hence, Slope $=\frac{1}{2}$ and cut-off voltage $=0.7V$