How Does Current Change with Resistance in Constant Voltage Sources?

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Discussion Overview

The discussion revolves around the behavior of current through a variable resistor connected to constant voltage sources, specifically comparing ideal and real voltage sources. Participants explore the implications of Ohm's Law and the effects of varying resistance on current in these contexts.

Discussion Character

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

Main Points Raised

  • One participant asks how current changes as resistance varies from zero to infinity in a constant voltage source.
  • Another participant references Ohm's Law, suggesting that current is inversely proportional to resistance when voltage is constant.
  • There is a question about the differences between ideal and real voltage sources and how these differences affect current.
  • A participant highlights that real voltage sources have internal resistance, which affects the output voltage when current is drawn.
  • Clarification is sought regarding the definitions of ideal and real sources, particularly in relation to Ohm's Law and resistance's impact on current.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and seek clarification on the differences between ideal and real voltage sources. The discussion does not reach a consensus on the implications of these differences.

Contextual Notes

Participants mention the internal resistance of real voltage sources and its effect on current draw, but do not resolve how this compares to ideal sources. There is also uncertainty regarding the maximum current that can be drawn from a real source.

Who May Find This Useful

This discussion may be useful for individuals new to electrical engineering, particularly those interested in circuit theory and the behavior of voltage sources.

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Hey guys

I am new to Electrical Eng, i got a question to answer, it says that a variable resistor is connected to a " Constant Voltage Source", how does the current through the resistor changes as its resistance varies from zero to infinity?

I also need with the same question, but with a ideal constant Voltage source and real constant vol source!

Thanks
 
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Do you know Ohms Law? If so, see how the current is related to voltage and resistance. Remember, the voltage is constant.
 
Yeh V = R*I, Since for the first V = Constant, Then I = V/R, I = 1/r, but what is the difference between ideal, real, and voltage constant sources!,

thanks
 
There are many subtle differences, and one big one. What happens to the current draw from an ideal source as the load resistance goes to zero? Would you expect the same behavior from a real source?
 
Can u give me some definitions for ideal and real sources and how the ohm's law works with those! And how resistance affects the current in those sources.

thanks and sorry really new with circuits and all!
 
Real voltage sources have an internal resistance - draw it as a battery with a small resistor in series. Now image you have a 12V battery with an internalal resistance of 1Ohm, as you draw 1Amp from the battery there is a 1V drop across the internal resistor and so you only get 11V out. What's the maximum current you can draw from such a battery?
AN ideal source has a zero Ohm internal resistance.
 

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