Voltage of a battery and capacitors are the same

Click For Summary

Discussion Overview

The discussion revolves around the voltage across capacitors in a circuit connected to a battery, specifically questioning whether all capacitors in a circuit will have the same voltage as the battery and how the presence of additional components, like a light bulb, affects this scenario. The scope includes conceptual understanding and technical reasoning related to circuit behavior.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions if all capacitors connected to a 12V battery will have the same voltage, suggesting that they might take their "maximum voltage" regardless of setup.
  • Another participant responds that whether all capacitors have the same voltage depends on the circuit configuration, stating that if connected directly to the battery, they will charge to 12V.
  • A participant expresses confusion about the voltage across capacitors in a specific circuit setup and asks what information is needed to determine the capacitance of each capacitor.
  • One participant asserts that not all capacitors will have the same voltage, providing an example where two capacitors could have a combined voltage that exceeds the battery voltage, thus violating charge conservation.
  • Another participant mentions that understanding charge conservation and the relationship between charge, capacitance, and voltage (Q=CV) is essential for solving these problems.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether all capacitors will have the same voltage in a circuit. There are competing views regarding the conditions under which capacitors charge to the battery voltage and how additional components like light bulbs influence the circuit.

Contextual Notes

Participants highlight the importance of circuit configuration and charge conservation principles, indicating that assumptions about the arrangement of components can significantly affect the outcomes. There are unresolved questions about specific circuit setups and the implications for voltage across capacitors.

oneplusone
Messages
127
Reaction score
2
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?
 
Physics news on Phys.org
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:

Figure_20_05_10a.jpg


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.
 

Similar threads

High School Some Questions about Electric Current/Capacitors to help my understanding
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Some questions about capacitor discharging
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Video: 'How electricity actually works'
  • · Replies 30 ·
2
Replies
30
Views
4K
High School Troubleshooting Battery Internal Resistance Measurements
  • · Replies 105 ·
4
Replies
105
Views
13K
Undergrad Rise in Voltage across a battery
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Voltage across a Capacitor More than the Source Voltage?
  • · Replies 9 ·
Replies
9
Views
5K
High School Batteries in Parallel Arrangement
  • · Replies 11 ·
Replies
11
Views
3K
Engineering Voltage in capacitors within an Energy Harvester
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Help Solve Voltage Homework Questions for Engineering Student
  • · Replies 8 ·
Replies
8
Views
3K
Graduate What is a Capacitor: Definition, Summary & Equations
  • · Replies 1 ·
Replies
1
Views
2K