Inductor filters AC ripples.

dharanimoka

Joined Jan 29, 2018
18
Inductor filters ac ripples to smothen the current waveform, so what exactly happens while filtering and how does that help in getting a near about dc current in rectifiers. Also because the capacitor filters the dc and dc gets stored in the form of energy in C which helps in maintenance of the dc output voltage. So how inductor does the same for the ac ripples?

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Papabravo

Joined Feb 24, 2006
17,245
The differential equation for the voltage across an inductor says it is proportional to the rate of change of the current through it. That's a fancy way of saying that an inductor offers little or no opposition to DC or very slowly changing AC current. The faster the current through the inductor tries to change the more the inductor tries to oppose the change by developing a voltage drop. The constant of proportionality is just the inductance L. The differential equation for the voltage across a capacitor says it is proportional to the integral of the current through the capacitor. That is a fancy way of saying that a capacitor offers a very large opposition to DC or very slowly changing AC. It offers little or no opposition to high frequency AC. In the limit, as frequency approaches ∞, it becomes a short circuit.

It is common, on the output of a power supply, to use a pi-filter consisting of a series inductor, and two shunt (to ground) capacitors. Low opposition to DC, high opposition to AC. That's the long and the short of it.

MisterBill2

Joined Jan 23, 2018
9,797
There is a lot more to a filter inductor than just resisting AC current. The inductance stores energy in the megnetization and then releases it in attempting to keep the current constant. The TS really needs to get hold of a textbook and see the much more detailed explanation of what I just stated. It is really quite interesting.

Papabravo

Joined Feb 24, 2006
17,245
There is a lot more to a filter inductor than just resisting AC current. The inductance stores energy in the megnetization and then releases it in attempting to keep the current constant. The TS really needs to get hold of a textbook and see the much more detailed explanation of what I just stated. It is really quite interesting.
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