Transistor - Stages

Description:

Input voltage in given by –

V_BB = V_BE + I_BR_i

From the above equation we can conclude that –

I_B α V_BB

The voltage across the circuit between emitter and collector i.e. output voltage in given by –

V_CE = V_CC − I_CR₀

As we know that unless I_B starts, I_C cannot start i.e. when I_B = 0, I_C = 0

I_C α I_B

Graph between input voltage and output voltage is –

Observations

As the input voltage (V_BB) increases, the base current (I_B) increases and collector current (I_C) also increases, this results in reduction of output voltage.

The output voltage is maximum in the cut-off stage, it decreases as the collector current increases this is known as active stage and becomes constant in the saturation stage.