If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

## Physics library

### Course: Physics library>Unit 12

Lesson 2: Circuits with capacitors

# Capacitors in parallel

A capacitator is a device that stores electrical energy in an electrical field. This video discusses the behavior of two capacitors connected in parallel. It compares two capacitators, and shows how to calculate the amount of charge each will receive. Finally, it discusses how to find the equivalent capacitance of the two capacitors combined. Created by David SantoPietro.

## Want to join the conversation?

• Ok, I'm slightly confused. Why the capacitors with the bigger capacitance have the lower Voltage? I understand the formula, I just would like a different interpretation to it.
• What happens if we hook up a resistor and a capacitor with the same battery in parallel and in series?
• In a series circuit a capacitor will initially allow current as if the resister is the only thing in the path but as the capacitor gains a charge it will limit the current until it is charged to the maximum voltage and then stop current flow. In a parallel circuit the capacitor will initially act like a short across the resister ans all of the current will flow through that branch until the capacitor is charged to the batteries voltage and the circuit will act like only the resister is in it.
• Help. How come for capacitors in series the total charge of the equivalent capacitor is the charge of each capacitor and for capacitors in parallel the total charge of the equivalent capacitor is equal to the sum of the charge stored by each capacitor ?
• Why is he showing the charges getting stripped off of the right sides of the Capacitors and not getting provided from the battery ?
• Charges are not provided by the battery. Energy is provided by the battery. The energy is used by the charged particles in the metal, as metals have delocalised electrons which gain this energy, the electrical potential energy to move from the positive terminal to the negative terminal, which you see on the left hand side. They do not flow back to the positive terminal due to the insulating material between the plates and hence, capacitors store energy and the material which the capacitors are made up of, the charged particles, use this energy to move back to the positive terminal when the circuit is complete. Hope I was able to answer your question and provide some depth to your understanding.
• What if one of the capacitors is different? As in, what if instead of their positive sides matching, one capacitor has it's respective positive side to the right and the other capacitor has its negative side pointing to the right?
(1 vote)
• With one battery that is impossible because the electrons flow in one direction, from the negative to positive, which gives the capacitors its charges.
• In the second problem would it be wrong to solve for the capacitances of capacitors in series first then add capacitance of parallel? What is the reason to do so?
• In the last bit of the video, finding the individual charges of the capacitors in parallel, would it also be possible to simply multiply the total charge of the equivalent capacitor by the proportion of each capacitor in relation to the total capacitance? e.g. doing 54 * 3/9 to find the charge of the 3F capacitor and 54 * 6/9 to find the charge of the 6F capacitor. I know it works for this problem, but is this a generally acceptable way of doing things?
• If there were two capacitors in parallel and C1 was charged but C2 was not, but C2 had double the capacitance of C1, when you connect the two, how much charge would be transferred to C2?
• If they are in parallel, the potential difference V has to be the same for each capacitor. See if you can take it from there.