Physics Question on Semiconductor electronics: materials, devices and simple circuits

Question

Graph of input characteristic of common emitter amplifier is

Answer 1

Solution

The input characteristics of common emitter amplifier is the curve between base current $I_B$ and base-emitter voltage $V_{BE}$ at constant collector-emitter voltage $V_{CE}$ .

The input characteristics can be determined by the circuit shown in figure. Keeping $V_{CE}$ constant (say at $0 V$ ), note the base current $I_B$ for various values of $V_{BE}$ .
Then, plot the readings obtained on the graph, taking $I_B$ along Y-axis and $V_{BE}$ along X-axis. This given the input characteristic at $V_{CE} = 0 V$ . Following a similar procedure, a family of input characteristics can be drawn. These curves are similar to as shown in option (b )