Answer to Question #85354 in Electric Circuits for Anand

Question

Why is it necessary in the case of cascade amplifier to use coupling network between the two stages?

Answer 1

Because quality of a signal for directly connected stages will be very low. Every next stage will have more noise (noise as a part of a signal is being amplified too), the bandwidth will decrease and so on. The couplings generally used are RC, impedance and transformer coupling. RC coupling implies using resistors and capacitors in order to block direct current. Transformer coupling is used when the stages have different impedances. Impedance coupling works the same way as RC coupling, but a coil replaces the load resistor of the first stage.