Power of Ideal Voltage Sources: Is it Infinite?

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Discussion Overview

The discussion revolves around the concept of ideal voltage sources in electrical engineering, specifically questioning whether such sources can be considered to have infinite power due to their constant voltage output regardless of the current drawn. The scope includes theoretical considerations and practical implications in circuit analysis.

Discussion Character

  • Conceptual clarification
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that ideal voltage sources can be considered to have infinite power because they maintain a constant voltage without internal resistance affecting the output.
  • Another participant compares the concept of ideal voltage sources to an "irresistible force or an immovable object," indicating a philosophical perspective on the nature of such sources.
  • A different viewpoint emphasizes the practical utility of voltage sources, noting that in real-world applications, a source can be treated as ideal if its internal resistance is negligible compared to the load resistance.
  • Feedback mechanisms in circuits are mentioned as enhancing the effectiveness of voltage sources, although this effectiveness is limited to certain operational ranges.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding and interpretation of ideal voltage sources, with some agreeing on the theoretical aspects while others highlight practical limitations. No consensus is reached regarding the implications of infinite power.

Contextual Notes

The discussion does not resolve the complexities surrounding the definitions of ideal voltage sources and their practical applications, leaving open questions about the assumptions involved in treating real sources as ideal.

Who May Find This Useful

This discussion may be of interest to students and professionals in electrical engineering, particularly those exploring circuit theory and the behavior of voltage sources in practical applications.

alphaomega@ho
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hello,

in my course I read about ideal sources
- an ideal voltage source holds a constant voltage , no matter the currect it's giving
so can I conclude that those types of sources has an infinite power in itself ?
(power = voltage x current)
maybay a stupid question...

thank you
 
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Yes, for voltage sources. The reason being that there is no internal resistance of the source. If there were, the voltage would sag (decrease) due to sourcing currents.

Welcome to PF
 
It's like an irresistible force or an immovable object. Just a concept.
 
thank you for your replies !
i am studing engineer and want to fully understand everthing
 
I might point out that the concepts of current and voltage sources are very useful because of the actual values of quantities you deal with in most practical electrical problems.
To get 'near enough' to a voltage source, all you need is the source resistance to be a small fraction of the resistance of the load and then you can 'ignore' source resistance in your calculations.
A 'reasonable size' fully charged battery can usually be treated as a voltage source when connected to a 'typical' small electronic circuit.
The collector of a transistor can very often be treated as a current source when the collector load has a value of even 100kΩ.

Using feedback in circuits involving amplifiers makes the effectiveness of a voltage or current source even better because the circuit does its damndest to maintain the volts or current it 'wants'. But the constancy will only hold over a limited range of values - after which the amplifier may run out of steam.
 
thank you for the replies,

I think I understand it now
do you have also a couple of good examples/excersis about law of Kirchhoff/supersposition/star-delta transformation/thevenin - norton equivalence

thank a lot !
 
alphaomega@ho said:
do you have also a couple of good examples/excersis about law of Kirchhoff/supersposition/star-delta transformation/thevenin - norton equivalence

Do you have a couple of good questions about any of those?
 
not exactly, I understand the priciples
but inmy course there aren't a lot of excersises so...

thank anyway
 
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