Electronics & Software – Tips & Guide


Why does the capacitor blocks DC but not AC

Why does the capacitor blocks DC but not AC?

a capacitor is like a buffer. you can fill it up to full. because a lot of capacitors are small, the filling time is very short. and when it is full, there will be no current, so it blocks the DC current.

in ac it will fill and empty. fill and empty etc. so it will blocks as if it did not block the alternating current.

After connecting the capacitor to the direct current, the capacitor plates charge in seconds or even seconds. and therefore, leaving no current through them.

While it changes direction after each half cycle, charging and discharging take place simultaneously in a capacitor. the capacitor is represented by 2 plates separated by an insulator … when a source of direct current is connected to it + the charges accumulate on the positive plate and the charges 5 accumulate on the 5 plates .

After a certain time all + and 5 charges will accumulate and when a charge will be connected, it will act now as a battery and will discharge to charge . simply that the meterial insulation b / w to the plates The air conditioning plates will charge alternately and will charge and discharge continuously

inside a capacitor, there is a material called dielectric. it improves the capacity but, by nature, it is a bad conductor or insulator. it does not allow the direct current to flow.

A voltage change of v volts, on a capacitor plate causes the shuffling of the charges so that the voltage on another plate also changes by v, so that the voltage across the capacitor remains constant.

a change in a plate is reflected by a change in another plate, so it appears that the change has passed through the capacitor and that the alternating current has passed through the capacitor.

capacitor is some 2 plates with insulator between them. therefore, in reality, it passes neither direct current nor alternating current. it blocks both!.

What happens in the case of AC is that the capacitor charges in half a cycle and discharges into the other half when the supply reverses the polarity. therefore, the current flows, not in the capacitor, but in the loop in the form of a charge and discharge cycle (hence an alternating current).

in the case of direct current, it will charge quickly (depending on product rc) and stop. therefore, there is no charging current at zero (practically / theoretically, it will take an infinite time to address it).

since a permanently applied voltage (ie) is involved, a capacitor is open circuit; these 2 “parallel plates” are not connected, so they lead nothing. then, dc is blocked.

One capacitor works – it’s useful – because when you apply a load to one plate, the accumulating electric field will have an equal and opposite effect on the charge buildup on the other plate. Of course, the same dipole effect occurs when you also apply DC, but once you have charged the capacitor at the first moment, you apply DC, no current flows.

but it changes all the time and the electric field makes so that the accumulation of charge on the opposite plate changes all the time too.

Thus, a capacitor will pass the current in both directions – up to a certain limit determined by the capacity of the capacitor – through this capacitor. Thus, a capacitor does not block the AC current (although the value of the capacitance and other circuit parameters determine the amount of current flowing and how often).