Capacitor-input or choke-input filter?

[Pagedown]

Capacitor-input or choke-input filter for power supplies?

Whats the difference and when to use them?

 

[berkeman]

Capacitor-input or choke-input filter for power supplies?

Whats the difference and when to use them?

Can you give some examples?

For AC Mains connected switching power supplies, you will generally have a line filter that has both chokes and caps in it. One of the main tasks of the line filter is to keep the switching noise of the power supply out of the AC Mains, in order to meet conducted emissions limits set by the FCC and other governmental agencies.

Depeding on the power source, you may put filtering between the power source and the input to a switching power supply, to help prevent feed-forward stability issues that could be caused by the input noise.