Q$4V_{}=0\mathrm{.}7V$ for both diodes

$($a$)$ Specify the shape and magnitude of input waveform in order to obtain $I_i-V_i$ and $V_o-V_i$ characteristics of given circuit

$($b$)$ Obtain $I_i-V_i$ and $V_o-V_i$ characteristics indicating all critical current and voltage levels

Answer:

$-4\mathrm{.}3V10\mathrm{.}7V$

$D_1$ and $D_2$ OFF

$D_{1}ON,D_2$OFF

$D_1$ and $D_{2}ON$