Question

Draw the circuit diagram and explain the working of CE amplier. Also mention any two applications.

Answer 1

The power supply V_cc, resistors R₁, R₂, R_c and R_E provide required DC bias for the transistor, C₁ and C₂ are blocking capacitors which allow ac and block dc. The bypass capacitor C_E bypass es ac at the emitter to ground.

During positive half cycle at the input signal, forward bias on the emitter base junction increases. Hence the currents i_b and i_c increase. As a result, i_c R increases and V decreases because V_CE = V_CC - i_cR_c

Thus we get negative half cycle at the output. During negative half cycle of input signal, forward bias on the emitter junction decreases. Hence i_b, i_c decrease and i_cR_c also decreases. As V_CB = V_CC – i_cR_c , V_CE increases.
Thus, we get positive half cycle at the output.
Thus a phase shift of 180° exists between the input and the output.
Applications: It is used as AF amplifier, RF amplifier and signal generator.