How do capacitor block the DC component and inductor block AC component?

[zio_nneo]

As we all know that capacitor block the DC componet and the inductor block Ac componet. Can anybody explain me what is the mechanism behind this ?

 

[Ajish Babu S]

Re: Capacitor

Hi

Check the following thread



with Regards

Ajish Babu S

 

[neils_arm_strong]

Capacitor

A capacitor blocks DC component but an inductor does not entirely block AC( it provides finite resistance to AC).This can be easily understood if you write the capacitive and inductive imedences in terms of Laplace transforms or fourier transforms.

Zc=1/(j*2*pi*f*C)
Zl=j*2*pi*f*L

 

[A.Anand Srinivasan]

Re: Capacitor

in the case of a capacitor the charges on one plate is reciprocated with equal charges of opposite polarity on the other plate due to attraction (equal charge to keep the cap electrically neutral)... when there is a change in the charges on one plate it is replicated in the other and results in current flow.... in the case of dc there is no change in charges and hence capacitor blocks DC......

In the case of inductor it develops a opposing field as given by lenz law,,,,,,,, this results in increase of impedance with frequency and the inductor effectively blocks AC............

 

[sivakumar_tumma]

Re: Capacitor

As we all know that capacitor block the DC componet and the inductor block Ac componet. Can anybody explain me what is the mechanism behind this ?

I got one explanation about the inductor blocking the AC component. As you know, inductor's leg can't be opened when currnet is flowing in inductor. So, when dc volatge is applied to inductor and current will be rising upwards, finally to remove inductor's leg the current has to be decreased: at this time voltage will be reverse to the polraity of rising current.

If you charge and discharge for equal times, the avarage volatge across inductor will be zero.

 

[emadi]

Re: Capacitor

the mechanism of capacitor is based on charging and decharching.
In loaw frequency the charging and decharging is very low speed an capacitor acts as an open circuit and in high frequency the capacitor will do this very fast and act as a short circuit

 

[sxunxs]

Re: Capacitor

in DC, when the capacitor reaches its peak voltage, charging stops thereby stopping the flow of DC . whereas in AC, when the capacitor reaches its peak voltage, AC changes its polarity and discharges the capacitor. this repeats as fast as the frequency of the source. this cycle allows AC to pass through capacitors.

 

[bmwcoupe]

Re: Capacitor

you can see it deirectly from the following equations :
for INDUCTOR :
V = L * DI/DT , you can see what will happen if DI=0

for CAPACITOR : I = C * DV / DT , you can see no current flow if DV = 0 V

thats it ....