FILTER CIRCUITS

The main function of  filters  are to convert  rippled output of rectifier circuit to produce a pure dc signal. The main components in the filter circuits are capacitors and inductors. In filter circuits the capacitors charges when the voltage or current increases and it discharges when the current or voltage decreases. The inductors in the filtering circuits uses its self  induction property  to make the rippled signal into a dc signal. In the case of inductor when the current increases above a certain value then it will induse a current in the opposite direction to the net current so the net current will decrease. When the current decreases below a certain value then the inductor produses a current in the direction of the net current so the net current increases. So by using an inductor in series with the rectifier out put we will get a small rippled signal . 

SHUNT CAPACITOR TYPE FILTER

In this type of filter the output of the rectifier is connected parallel to a capacitor before it is connecting to the load resistor. The capacitor will reduse the ripples by passing ac components through the capacitor that is by continouse charging and discharging of capacitor. The required capacitor is selected by calculating the time constant  that needed for  the filter circuit .

 

 

SERIES INDUCTOR TYPE FILTER

In this type of filter circuit an inductor is connected series to the rectifier output. The self induction property of the inductor reduces the ripples in the signal. The series inductor type filter is normally used with fullwave rectifiers and bridge rectifiers. This type of filters will not use with half wave rectifier because of the low efficiency .

 

L SECTION FILTER

In this type of filters capacitors and inductors are used. The out put of the rectifier is connected parallal to the capacitor and series with the inductor. The parallel capacitor passes the ac components in the output of the rectifier. The series inductor reduces the ripples in the output. This type of filter also known as choke filter

 

 

 

 

 

 

π SECTION FILTER

In this type of filters two capacitor and one inductor is used. The two capacitors are connected parallael to the rectifier output. And the inductor is connected series  in between the parallel capacitors. It is one of the efficient  filter .

 

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