# Voltage of a battery and capacitors are the same

• oneplusone
In summary, the conversation discusses the voltage of capacitors in a circuit with a 12V battery and how it may be affected by the addition of a 4V light bulb. It is noted that the voltage of capacitors depends on the circuit and that the addition of a light bulb may slow the charging process but should not change the final voltage. The speaker also mentions their confusion with problems involving finding capacitance and explains that knowledge of charge conservation and potential in a wire is needed to solve such problems.
oneplusone
I was watching this video: http://www.youtube.com/watch?v=P8A1U-RZDao&index=7&list=PLLUpvzaZLf3Jv7AjU5pfY8s25-QBCfdIZ
and at around 6 minutes, I got confused. Ill summarize it below in case the link does not work:

If you have a circuit which consists of a battery which is 12 volts, and a lot of capacitors…what is the voltage of the capacitors? Are ALL of them 12 V regardless of how they're set up, and the size of it? I heard something about capacitors taking their "Maximum voltage" always.

Also, how would this change if you add a 4V light bulb?

Did you mean to link the video "Dielectrics in Capacitors and Otherwise" or something else? The video does not look related to your questions.

oneplusone said:
Are ALL of them 12 V regardless of how they're set up, and the size of it?
It depends on the circuit. If their terminals are connected to the terminals of the battery (via a cable as in 6:00), they will charge to 12 V.

Also, how would this change if you add a 4V light bulb?
It acts like a resistor, and will slow the charging process. It should not change the final voltages if it is a regular light bulb (i.e. not LEDs).

I can't find the correct video for some reason . I ll check later.

Suppose you have something like this:

and it's connected to a battery . Would ALL the capacitors have the same voltage across it?
I'm mainly confused on problems like: "you stick a 12 volt battery to a circuit like this…now find the capacitance of each capacitor". Like what would you need to know to solve it?

Would ALL the capacitors have the same voltage across it?
No.
As an example, if the leftmost two capacitors would both have 12V across it, the total voltage across this side would be 24V - but we know the two sides have a difference of just 12V.

In addition, the same voltage for both capacitors would violate charge conservation if we start charging it from zero.

Like what would you need to know to solve it?
Just charge conservation, Q=CV and knowledge that the potential is the same everywhere in a wire.

The voltage of a battery and capacitors are not necessarily the same. While the battery may have a voltage of 12 volts, the voltage of the capacitors will depend on how they are connected in the circuit. In the video you mentioned, the speaker is discussing the concept of capacitance and how capacitors can store charge. The voltage of a capacitor is determined by the amount of charge it can hold, which is affected by the size and configuration of the capacitor. Therefore, the voltage of the capacitors in the circuit may not all be 12 volts.

As for the "maximum voltage" concept, this refers to the maximum amount of voltage that a capacitor can handle before it becomes damaged. This is important to consider when designing circuits to prevent damage to components.

Adding a 4V light bulb to the circuit will affect the voltage distribution in the circuit. The voltage across the light bulb will be 4V, while the voltage across the capacitors may decrease depending on their configuration and the amount of charge they are holding.

In summary, the voltage of capacitors in a circuit is not necessarily the same as the battery voltage and can vary depending on the capacitance and configuration. It is important to consider the maximum voltage a capacitor can handle when designing circuits. Adding components, such as a light bulb, can also affect the voltage distribution in the circuit.

## 1. What is the difference between voltage of a battery and capacitors?

The main difference between the voltage of a battery and a capacitor is that a battery is a source of energy that maintains a constant voltage, while a capacitor is a storage device that can hold a certain amount of charge.

## 2. Can the voltage of a battery and a capacitor be the same?

Yes, the voltage of a battery and a capacitor can be the same. This can happen when the capacitor is fully charged and its voltage is equal to the voltage of the battery.

## 3. How is the voltage of a battery and a capacitor measured?

The voltage of a battery and a capacitor can be measured using a voltmeter. The positive terminal of the voltmeter is connected to the positive terminal of the battery or capacitor, and the negative terminal is connected to the negative terminal. The voltmeter will then display the voltage reading.

## 4. Is the voltage of a battery and a capacitor affected by the same factors?

No, the voltage of a battery and a capacitor can be affected by different factors. The voltage of a battery can be affected by the type of battery, its age, and the external circuit it is connected to. The voltage of a capacitor can be affected by its capacitance, the charge on it, and the material it is made of.

## 5. Can a battery and a capacitor be used interchangeably in a circuit?

No, a battery and a capacitor cannot be used interchangeably in a circuit. They serve different purposes and have different properties. A battery is used as a source of energy, while a capacitor is used for storing and releasing electrical energy. Additionally, batteries and capacitors have different voltage and current capabilities, which can affect the performance of a circuit.

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