Discussion in 'General Electronics Chat' started by chaitu123, Sep 7, 2009.
Q) why the capacitor blocks the D.C component in the applied input signal?
dc current needs a continuous circuit loop between the power supply terminals. The capacitor forms a discontinuity because it is made of two conducting plates with a small nonconducting space between them. This gap stops the current from flowing.
In a series RC circuit that's fed with a dc signal that turns on a time t=o, the only current that flows is the current that charges up the cap to the applied voltage level. Caps store charge and later release it, but they cannot conduct DC since there is no DC path thru them. Take any small cap (up to 0.1uF) and put it across your ohmmeter and youll see that it reads infinity since no contimuous current can flow. You may see an initial reading on the ohmmeter which is the cap charging up.
It's simple physics.