An essential requirement of a well designed choke input filter is:

Concept:

The choke input filter, also known as the L-Section filter is a combination of an inductor filter and a capacitor filter. It consists of an inductor in series and a capacitor in shunt with the load R_L. It is used to smooth out the pulsating dc obtained from the rectifiers.

Circuit of Choke Input Filter:

Solution:

The inductor (choke) allows the dc component to pass and restricts the ac component of the input. For this, XL >> XC

If any component of the ac is still present after passing through the inductor, it is bypassed through the capacitor in the shunt. For that, the impedance of the capacitance must be very less than the resistance R_L. Hence, X_C << R_L. 

For the well-designed choke input filter with a high load, 

\(R_L>>X_L>>X_C\)

Hence, X_L is much greater than X_C at the input frequency.

Additional Information

For a half-wave rectifier, \(R_L>>\omega L>>{1 \over \omega C}\)

For a full-wave rectifier, \(R_L>>2\omega L>>{1 \over 2\omega C}\)