Capacitors connected in series?

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    Capacitors Series
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SUMMARY

The discussion centers on the behavior of capacitors C1 and C2 when connected in series and then reconnected in various configurations. It is established that when capacitors are disconnected from a battery and then reconnected, the charge does not simply double; instead, the charges equalize, resulting in zero net charge if connected incorrectly. The participants clarify that reconnecting capacitors in parallel after disconnection leads to different charge distributions, and the importance of understanding the zero-sum nature of charge in circuits is emphasized. The conversation also touches on the implications of reconnecting capacitors with reversed polarity and the necessity of a voltage source for further charging.

PREREQUISITES
  • Understanding of capacitor behavior in electrical circuits
  • Familiarity with series and parallel connections of capacitors
  • Knowledge of charge conservation principles in circuits
  • Basic grasp of Ohm's Law and current flow
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  • Study the mathematical relationships governing capacitors in series and parallel configurations
  • Learn about charge conservation and its implications in electrical circuits
  • Explore practical applications of capacitors in energy storage and discharge scenarios
  • Investigate the Cockcroft-Walton generator and its use in high voltage applications
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Electrical engineers, physics students, and anyone interested in understanding capacitor behavior in circuits will benefit from this discussion. It provides insights into charge dynamics and practical implications for circuit design.

  • #31
re post #23 (Bottom left corner of the diagram)

The bottom capacitor goes from +Q, -Q to 0Q, +2Q. So the voltage polarity has reversed. That certainly looks like it's been discharged and recharged in the opposite direction :-)

A change from -Q to +2Q implies a current of 3Q flowed. Yet other nodes change from +Q to +2Q which is only an increase of Q. How is that possible if they are in series?
 
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  • #32
rumborak said:
Sorry, had not noticed the reversal of charges in case 3. But still, case 1 you can't really calculate like that. The formulas you are using presume ideal components; at the moment of your case 1 picture, you are short-circuiting ideal components. Meaning you have infinite current, and an unaccounted-for potential difference between the capacitors.
mmm, but i think all that in the paper doesn't hold unless c1 = c2, the final answers wouldn't change but the steps would change, for example in case 2 if c1 not equal c2 therefore Q1 will not be equal to Q2 but there summation still will be 2Q
 
  • #33
@CWatters, crap, you are correct, the picture is incorrect. The two right plates should read -2Q (top) and 0Q (bottom). Which would mean, when you cross them over, you are connecting a 2Q to -2Q. The reversal of polarity is what kills it in the end.

It was a nice idea, lol.

EDIT: Thinking about it more, there's also the argument that charges are a zero-sum game. If I create a 2Q somewhere, somewhere else must be -2Q. The only way of reconnecting it without massive discharge would be to find another 2Q potential. Which really could only come from another device.
Hmmmmm, got to think more about this.
 
Last edited:
  • #34
so i think case one would only be short circuit when c1=c2 :D , but if c1 not equal c2 so voltage will be distributed not equally between them (because in series) so i think it will not be shorted
 
  • #35
Throw a few diodes into the mix and you can make a high voltage charge pump..

http://en.wikipedia.org/wiki/Cockcroft–Walton_generator

220px-Cockcroft_Walton_voltage_multiplier_circuit.svg.png
 

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