Alternating Current. (When can we see it?)

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Discussion Overview

The discussion revolves around the visibility of flickering in alternating current (AC) light sources, specifically focusing on how slow the AC must be for flickering to be perceptible. The scope includes conceptual understanding and technical aspects related to different types of light bulbs.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions the frequency at which AC must operate for flickering in light bulbs to be visible.
  • Another participant suggests looking into the concept of persistence of vision and notes that incandescent bulbs flicker twice per AC cycle due to the nature of resistive heating.
  • This participant also mentions that the cooling time of the filament affects the perception of flicker and estimates a minimum frequency of around 10 Hz.
  • A different participant states that incandescent bulbs do not easily show flicker due to filament temperature, while fluorescent bulbs can be seen flickering at 60 Hz.

Areas of Agreement / Disagreement

Participants present varying views on the visibility of flicker in different types of bulbs, indicating that there is no consensus on the exact frequency at which flickering becomes perceptible.

Contextual Notes

The discussion includes assumptions about the properties of light bulbs and the effects of filament temperature, which may influence the perceived flicker. There are also references to empirical estimates without definitive measurements provided.

ScienceNerd36
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Hello there my fellow chemical structures!

I was just wondering the other day, while staring vacantly at a lighting fixture: How slow would the AC going back and forth through the light bulb have to be before you could see it flickering?

Any information would be much obliged.

Thanks in advance.
 
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You might want to investigate http://en.wikipedia.org/wiki/Persistence_of_vision" . A couple fine points with incandescent lighting: first, the filament will flicker twice for each AC cycle, since resistive heating is independent of current direction. Second, the filament won't go dark instantaneously but will cool down over a time period that depends on the thickness, material, and geometry of the filament. Empirically, I'd expect the minimum frequency to be on the order of 10 Hz, but I don't have a frequency generator handy; perhaps someone else does.
 
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Thanks
 
Incandescent bublbs don't easily show flicker because of the temperature of the filament. A flourescent bulb can be seen at 60 Hz.
 

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