Does filament size or resistance affect the brightness of a lightbulb?

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    Filament Resistance
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Discussion Overview

The discussion centers on the relationship between filament size, resistance, and the brightness of a lightbulb. Participants explore how these factors interact, particularly in the context of electrical power and current flow.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that higher resistance in a filament leads to increased brightness, assuming that more resistance correlates with a smaller filament size.
  • Another participant counters this by stating that with a constant voltage, a filament with lower resistance allows more current to flow, resulting in greater power output and thus increased brightness.
  • A subsequent post seeks clarification on whether increased current indeed causes the filament to glow brighter, indicating a need for further explanation.
  • One participant directs others to search for "resistive heating," implying it may provide additional insights into the topic.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between filament size, resistance, and brightness, with no consensus reached on the correct interpretation of these interactions.

Contextual Notes

Participants do not fully explore the assumptions underlying their claims, such as the effects of voltage stability or the specific characteristics of different filament materials.

Who May Find This Useful

Individuals interested in electrical engineering, physics of light, or those studying the principles of resistive heating may find this discussion relevant.

southern69
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Does anyone have a clear understanding on the relationship between the filament size of a lightbulb and the wattage? I was under the impression that resistance causes the filament to heat up and glow, so the more resistance the brighter the light bulb. A filament with more resistance, then, would have to be smaller. However I have read that a larger filament causes a bulb to grow brighter. Is this true, and why?
Thanks
 
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It is true, because the wall is in essence a constant voltage source. Given a constant voltage and a purely resistive load (a decent approximation), a filament with half the resistance will allow twice the current through. Because power is V*I, for a constant V and twice the I (current), you will have twice the power.
 
Thanks. But are you saying that more current causes the filament to glow brighter? If this is true could you please try and explain it to me. (sorry)
 
google "resistive heating".
 

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