What Is the Relationship Between Charge, Voltage, and Capacitance?

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SUMMARY

The relationship between charge (Q), voltage (V), and capacitance (C) is defined by the formula Q = CV. In a practical scenario, when connecting two metal plates to a battery, one plate receives electrons while the other loses them, demonstrating charge transfer. The concept of capacitance is fundamentally linked to the proximity of the plates; if they are infinitely far apart, capacitance (C) becomes zero, resulting in no induced charge. Thus, capacitance is a measure of how two objects influence each other's ability to store charge when they are in close proximity.

PREREQUISITES
  • Understanding of basic electrical concepts such as charge, voltage, and current.
  • Familiarity with the capacitance formula Q = CV.
  • Knowledge of how batteries function in electrical circuits.
  • Comprehension of the physical principles governing electric fields and charge distribution.
NEXT STEPS
  • Explore the concept of electric fields and their influence on charge distribution.
  • Learn about different types of capacitors and their applications in circuits.
  • Investigate the effects of distance on capacitance and charge storage.
  • Study the principles of circuit design involving capacitors and batteries.
USEFUL FOR

Electrical engineers, physics students, and anyone interested in understanding the fundamentals of capacitance and its applications in electronic circuits.

daudaudaudau
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Hi. I'm trying to understand a couple of things.

When you put a piece of metal on, say the cathode of a battery, I suppose there is a charge transfer from the battery to the metal because the electrons on the cathode have a high potential energy? And so if I connect a piece of metal to both the cathode and another one to the anode, one piece should receive electrons and the other one should lose electrons.

But I cannot make this fit with the capacitance formula Q=CV, because if the two metal pieces are infinitely far apart, C=0 and then no charge is induced at all.
 
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Why do you want your plates to be infinitely far apart?
 
I think the "infinitely far apart" portion of your thoughts is the problem, not Q = CV. How do you connect two plates infinitely far apart to the same battery? How do you expect two objects infinitely far apart of exert an influence each other? Capacitance arises because two objects near each other effect each others' ability to store charge.
 

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