Electromagnetic coil and capacitors vs resistance

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Discussion Overview

The discussion revolves around the formulas used to calculate energy stored in electromagnetic coils and capacitors, and the relationship of these formulas to resistance. Participants explore the similarities and differences in the equations for energy storage and power dissipation, questioning the underlying principles and patterns.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that the formulas for energy stored in coils (U=0.5LI²) and capacitors (U=0.5CV²) appear similar, suggesting a parallel between inductance (L) and capacitance (C).
  • Another participant questions the expectation for the formulas to be the same, emphasizing that resistance (R) does not store energy and that U=RI² represents power, not energy.
  • A participant proposes that the energy for resistance could be expressed as U=RIq, seeking clarification on the energy equations for coils and capacitors.
  • Further clarification is provided that the energy lost in resistance is defined as an integral of power over time, suggesting that the similarities in the forms of the equations may be coincidental.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between the formulas for energy storage in coils and capacitors versus the power dissipation in resistance. There is no consensus on whether the similarities in the equations indicate a deeper connection.

Contextual Notes

Participants highlight the distinction between energy storage and power dissipation, indicating that the equations for resistance do not follow the same pattern as those for coils and capacitors. The discussion remains open regarding the interpretation of the formulas and their implications.

Who May Find This Useful

This discussion may be of interest to those studying electrical engineering, physics, or anyone curious about the relationships between energy storage in inductors and capacitors, and power dissipation in resistors.

Mohammad Hunter
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I'm not really sure if this is even scientific but while calculating how much energy is stored in electromagnetic coils and capacitors, pretty much the same formula is used:
For electromagnetic coils it's U=0.5LI2
For capacitors it's U=0.5CV2
Why I think they're the same is that in a sense L to coils is sort of the same as C to capacitors. Same goes for V and I
The formula used for resistance is pretty much the same( well resistance doesn't store energy, uses it) with a slight difference which is there's no 0.5
U=RI2
Why don't we have the same pattern for resistance? Are these formulas even realevant?
 
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Why would you expect them to be the same? As you said, R does not store energy. and ##RI^2## is not energy it is power. See my signature below.
 
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anorlunda said:
Why would you expect them to be the same? As you said, R does not store energy. and ##RI^2## is not energy it is power. See my signature below.
So energy for resistance is actually U= RIq?
But what about coils and capacitors? Are those actually the same formula adjusted for coils and capacitors? If so, what is the mother formula. Cause the conserved energy in movement shows the same pattern of K=0.5mV2 which you could say that mass to an object is sort of like L to coils and C to capacitors
Too many questions, sorry :)
 
Mohammad Hunter said:
So energy for resistance is actually U= RIq?
a

No, the energy lost in a resistance is ##\int RI^2\, dt## Or, if the power P is constant for a time T, then energy is P times T.

For the others, just consider the similarities in form of the equations to be coincidences.
 
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anorlunda said:
a

No, the energy lost in a resistance is ##\int RI^2\, dt## Or, if the power P is constant for a time T, then energy is P times T.

For the others, just consider the similarities in form of the equations to be coincidences.

Ohhhh Thank you
 
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