What is need for connecting resistance Rs in series with PN diode?

Connecting a resistance ( R_s ) in series with a PN diode helps to limit the current flowing through the diode, protecting it from damage due to excessive current. It also allows for better control of the voltage across the diode, ensuring it operates within its safe range. Additionally, this configuration can improve the stability and performance of the circuit by providing a predictable current flow, especially in applications like signal modulation or voltage regulation.