Filters

To start with let me give you a preliminary idea about a filter.A filter can be natural one,biological one,and also of a psychological one.Here ,I will mention about a technical filter which basically filters out to be FILTER in the subject electronics.So,in many electronic circuits we require direct current(DC) and to convert AC to DC we require a filter which is practically of many types such as inductor filter,capacitor,pi-filter,capacitor-inductor filter and many more.I have mentioned only those filters that i am going to explain on my posts respectively.  Let me excite you by a promise-'you will become expert on this topic provided you have some pre-knowledge about the subject and concentration lapses are/should be negligible'.SO GEAR UP.........
Let me give you a image describing the waveform.

Thye first one is  is taken from the output of an rectifier circuit (e.g.Diode rectifier) and this output voltage is passed on to the filter circuit and the output is similar to the 2nd mage above.Now ,let us start this interesting topic by understanding the inductor filter.

• INDUCTOR FILTER

From the above figure you can observe that the inductor(L)is placed between the rectifier circuit and the load resistance(RL).Now as i have told you that the rectifier output voltage consists of ac as well as dc components as it is a sinusoidally varying curve.When ac signal is passed through the inductor it provides high impedence to it thereby blocking the signal completely(hint-emf is induced due to constantly changing magnetic flux) but when a dc signal is passed through it,the inductor provides very low impedence and thereby allowing the signal to pass through.So,the ac component is removed but the dc component is allowed to pass.Now,concentrate on the first image where due to the ac components ripple exists.Ripples are considerably decreased but you can't weed it out completely.100% removal is available only in ideal cases(but ideal cases don't occur in reality).

Just look at the image above where i have given a formula for ripple factor denoted by gamma.

RL-This is the load resistance(ohms).

L=This is the inductance in Henry.

w(omega)=Frequency is in Rad/s.

You can observe from the above equation that the ripple factor increases with increasing load resistance but decreases with increasing inductance.

• PROBLEM TO ENGAGE YOUR NEURONS:-

The output voltage of a full wave rectifier circuit is fed into an inductor filter.Design inductor filter if the ripple factor of filter output voltage is 4% for a load resistance of 100 ohm and the supply frequency is 50Hz.(Ans-L=1.53H)

Stay tuned for more if you have any problems just hit me up.