Voltage or current in solenoid?

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Discussion Overview

The discussion centers around the relationship between voltage (V) and current (I) in solenoids, specifically regarding which factor contributes more to the force exerted by the solenoid. Participants explore the implications of Faraday's laws and Ohm's law in this context, considering the role of the number of turns in the solenoid.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant inquires whether voltage or current contributes more to the force of a solenoid, noting the interdependence of V and I as described by Ohm's law.
  • Another participant asserts that the induced magnetic field in the solenoid depends solely on current, referencing the equation B = μ n I, where B is the magnetic field, μ is the magnetic constant, n is the turn density, and I is the current.
  • A different participant emphasizes that while current is directly related to the magnetic field, voltage is necessary to maintain current flow, suggesting that both factors must be considered in relation to other variables like the number of turns and resistance.
  • A later reply expresses appreciation for the insights shared, indicating an understanding that current strengthens the magnetic field while voltage is essential for maintaining current in the circuit.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether voltage or current is more critical for the force of the solenoid, as they present differing perspectives on the roles of each factor and their interdependence.

Contextual Notes

The discussion highlights the complexity of the relationship between voltage, current, and the resulting magnetic field, with participants acknowledging the influence of additional variables such as the number of turns and resistance in the wire.

falling cat
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Hi everyone,

I'm having some fun building solenoids for a project. I can't just leave "well enough" alone... I want to know how these things really work! I understand the concepts behind Faraday's laws, current in a wire, etc...

What I would like to find out is which gives more force to the solenoid, V or I? I know Ohm's law says I can't raise one without the other... But does the force depend on the voltage or current, assuming the number turns remains constant?

Thanks!
 
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What "force" are you asking about? If you are asking about the induced magnetic field through the solenoid, then it depends solely on current. The equation is given by: B = μ n I, where μ is the magnetic constant (permeability of free space), n is the number of turns per unit length (turn density), and finally I is the current. Think of it like this: Movement of charges (current) induces the magnetic field, not the energy carried per charges (voltage). Hopefully this was the question you were asking, if it were not, then you might want to consider rephrasing the question.
 
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falling cat said:
What I would like to find out is which gives more force to the solenoid, V or I?
The current is directly related to the magnetic field but, to cause a current to flow, a Voltage is needed.
It's a matter of considering all the variables. n, the number of turns will affect the Voltage that's required to pass a given amount of current because the resistance of the length of wire affects the current. There isn't a 'heirarchy' of variables; they are all relevant.
 
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Thanks for your insight guys!

The way both of you put it makes sense- current makes the field stronger, but the voltage is necessary to keep the current constant for a certain length.

Thanks again!
 

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