A common emitter amplifier circuit, built using an npn transistor, is shown in the figure. Its dc current gain is 250, R_C = 1k$$\Omega$$ and V_CC = 10 V. What is the minimum base current for V_CE to reach saturation ?

The reverse breakdown voltage of a Zener diode is 5.6 V in the given circuit.

The current IZ through the Zener is :

In the figure, given that V_BB supply can vary from 0 to 5.0 V, V_CC = 5V, $$\beta $$_dc = 200, R_B = 100 k$$\Omega $$, R_C = 1 k$$\Omega $$ and V_BE = 1.0 V. The minimum base current and the input voltage at which the transistor will go to saturation, will be respectively :

The output of the given logic circuit is :