How does a capacitor get charged?

In summary, a capacitor is charged when electrons from the negative terminal of a battery flow to one side of the plate, creating a negative charge. The positive plate is formed when electrons from the "positive plate" move to the negative plate against the electric field, creating a positive charge. This process creates a voltage potential between the plates, and the capacitor can be modeled as a short circuit before power is applied and an open circuit once it is charged.
  • #1
david888lee
7
0
So, I'm really confused on how a capacitor gets charged. I understand that electrons from the negative terminal of a battery flow to one side of the plate to make that side negative. However, I don't understand how the positive plate is formed.

From what I've been reading, it says that electrons from the "positive plate" move to the negative plate against the electric field (which I'm assuming is the electric field of the electron from -q to +q) , however I can't visualize how that's happening.


Hopefully someone can explain... been bugging me for a long time now. Thanks in advance!
 
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  • #2
The electrons are 'pushed /pulled' by the potential difference applied to the capacitor and take the long route around the circuit, via the power supply. The positive plate has the same number of electrons removed as appear on the negative plate. This also applies to a battery as it is charged.
 
  • #3
david888lee said:
So, I'm really confused on how a capacitor gets charged. I understand that electrons from the negative terminal of a battery flow to one side of the plate to make that side negative. However, I don't understand how the positive plate is formed.

From what I've been reading, it says that electrons from the "positive plate" move to the negative plate against the electric field (which I'm assuming is the electric field of the electron from -q to +q) , however I can't visualize how that's happening.


Hopefully someone can explain... been bugging me for a long time now. Thanks in advance!
An uncharged capacitor can be modeled by a short circuit. Current flows into the cap creating an abundance of electrons on one side of the dielectric and as a result there is a lack of electrons on the other side of the dielectric creating a positive charge. As a result an electric field is created which aligns the atoms of the dielectric creating a potential between the plates. The dielectric is an insulator so current does not pass through it but it is now poloarized. This voltage potential builds up (like water pressure when a hose is pinched) and will release this voltage as the circuit dictates. So the cap can be modeled as a short circuit the instant before power is applied to the circuit and as voltage builds and the cap becomes charged the cap can now be modeled as an open circuit with the full specified voltage acrossed it. Hope this helps.
 

What is a capacitor?

A capacitor is an electronic component that stores electrical energy in an electric field. It is made of two conductive plates separated by an insulating material.

How does a capacitor charge?

A capacitor charges by connecting it to a power source, such as a battery, which causes electrons to flow onto one plate of the capacitor, building up a negative charge. This negative charge repels electrons on the other plate, creating a positive charge. As more charge is added, the voltage across the capacitor increases until it reaches the same voltage as the power source.

How long does it take for a capacitor to charge?

The time it takes for a capacitor to charge depends on its capacitance, the voltage of the power source, and the resistance of the circuit. It can range from a fraction of a second to several minutes.

What happens if a capacitor is overcharged?

If a capacitor is overcharged, it can lead to a breakdown of the insulating material between the plates, causing a short circuit. This can result in the release of a large amount of energy, potentially damaging the capacitor and other components in the circuit.

How do I discharge a capacitor safely?

To discharge a capacitor safely, it is important to first disconnect it from any power source. Then, use a resistor or a specially designed discharge tool to slowly release the stored energy. It is important to follow proper safety precautions when handling capacitors to avoid electric shock.

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