Does AC go through capacitors and DC does not?

Question

An explanation would be nice. I looked in wikipedia, didn't explain it.

Answer 1

This is correct. A capacitor can be thought of as two parallel plates that aren't touching, each with a wire trailing off the end that goes to the rest of the circuit. Electrons can pile up in either plate (creative a negative charge on that plate). However, the more electrons that pile up on one plate, the more they resist additional electrons being squeezed in. So, a capacitor allows a small amount of charge to oscillate in its plates, but if you apply DC (constant) voltage, the electrons will flow briefly, but they'll all pile up in in one plate, and the current flow will quickly drop to zero.

A capacitor is usually drawn like this:

-----------| |----------------

Answer 2

A Crude Analogy.

Think of a person using a skipping rope.

The normal way of skipping is like DC (Direct Current, one direction), whereby the rope is moved in one direction, say clockwise and when it comes to the ground, the person skips over it.

When we think of AC (Alternating Current, two oppositing directions), we move the rope clockwise and then anti-clockwise and the pattern repeats itself. The person skips over the rope as it passes the ground.

Now, here is the important part. If the person decide to stand firm on the ground without jumping. Which method can still function? DC or AC?

You will realize that the DC will be Blocked. (You can swing the rope one way but it will be blocked) However for the AC, you can still continue swinging the rope, alternatively around the person. Although the person does not "skip" over the rope, the rope was able to cover practically the same area as before by using its ablility to move in both directions.

A capacitor works by way of Electrostatic or Electric Field principle. The capacitor plates can hold some charges during one cycle and release some charges during the reverse cycle. Hence it's ability to "pass through" the capacitor.

For a Direct Currect, since it only flow in one direction, it will just charge the capacitor once and that's it, no further conduction.

Answer 3

When a capacitor contains no charge, DC will go through it when a voltage source is connected to it. As the current flows through the capacitor, the capacitor charges and a voltage builds up across it. When the capacitor voltage equals the source voltage, there are two equal voltage sources facing each other and the current will no longer flow either way.

When an AC voltage source is connected to a capacitor, the source voltage drives current first one way and then the other so that an AC current flows. The AC current is proportional to the AC voltage, but the maximum current occurs when the voltage changed direction and goes through zero. When the AC voltage reaches a peak and starts decreasing, the capacitor current reverses direction and goes through zero.

Answer 4

Yes, but only up to a point.
The capacitor will limit current flow.
Each wave of the AC charges the capacitor up to it's total capacity, (idealy),.
Beyond that current is limited.

Answer 5

(+)---| |---(-)
the capacitor charges partway, then the polarity flips, so:
(-)---| |---(+)
the current can keep flowing, since the charge never stabilizes.

Answer 6

-----------(|)----------------