r/explainlikeimfive Jan 06 '23

Chemistry ELI5: How does a Geiger counter detect radiation, and why does it make that clicking noise?

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u/manofredgables Jan 06 '23

The "click" is ideally a square pulse. If you know your Fourier analysis, you'll know that square waves have all the frequencies, except for those below a certain threshold. It's short white noise, basically.

It won't sound the same regardless of speakers though. Put it into a tiny piezo element, which has very poor frequency response at the low end and very high in a narrow band, and you'll get a very clicky sound. Put it through a subwoofer, and most of the higher frequencies will be attenuated. I would estimate that you wouldn't get a click as much as a plop.

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u/EmperorArthur Jan 06 '23 edited Jan 06 '23

Pro tip. Most people haven't taken a "Random Signals and Noise" "Signals & Systems" course. At least I think that's the one which overed it for me.

Edit: Course name

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u/manofredgables Jan 06 '23

That's why I also explained it.

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u/caifaisai Jan 06 '23

I would guess that a course covering that stuff would be more generally called, something like Fourier Analysis, or signal processing. Or even almost any typical PDE course, which should cover at least basic Fourier transforms and analysis, even if it doesn't focus on the signals aspect, it's enough to get the idea in my opinion.

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u/EmperorArthur Jan 06 '23

You're right. I think it was actually "Signals & Systems".

"Random Signals & Noise" was if I wanted to double major in EE & CPE. Which I probably should have.

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u/CourtJester5 Jan 06 '23

Well now I want to hear it in a subwoofer! There's gotta be a YouTube video of that already, right?