# flashes and whining

**URL:** <https://boards.straightdope.com/t/flashes-and-whining/151974>\
**Category:** Factual Questions\
**Created:** [January 31, 2003, 10:38pm UTC](https://boards.straightdope.com/t/flashes-and-whining/151974 "2003-01-31T22:38:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jb\_farley](https://avatars.discourse-cdn.com/v4/letter/j/9d8465/32.png) [@jb\_farley](https://boards.straightdope.com/u/jb_farley)\
**Post date:** [January 31, 2003, 10:38pm UTC](https://boards.straightdope.com/t/flashes-and-whining/151974/1 "2003-01-31T22:38:26Z")

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hello.

no, this is not a PitRant asking why i never get flashed by old pervs in the park. although now that i think about it…

as a camera’s flash charges, there’s that high-pitched whining sound. why is that?

an old physics teacher (great teacher, but a bit on the physics-teachers’-urban-legend side), when i asked, said that manufacturers put a little whining thing in there. for some consumero-psychological reason, rather unclear.

what’s the deal? capacitors don’t make noise all that often, do they?

thanks,

jb

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**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\
**Post date:** [January 31, 2003, 10:57pm UTC](https://boards.straightdope.com/t/flashes-and-whining/151974/2 "2003-01-31T22:57:26Z")

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The whine is caused by the oscilating action of a feedback circuit which gradually increases voltage as the capacitor is charged (which is why the whine increases in frequency.)

There’s a more detailed explanation [here](http://www.howstuffworks.com/camera-flash3.htm).