aster Jan 29, 2022
looked up “how do car horns work” because I was curious and one of the related questions is “do car horns run out of honk” which is endlessly hilarious to me
Show threadaster 

to those wondering: contemporary car horns
don’t because they’re electric (it’s one of those things where a circuit rapidly switching on and off through a spring-like mechanism creates vibrations in a metal drum which create sound). so long as the battery has charge and the mechanism doesn’t break, they can honk endlessly!

air horns are a different story but most cars don’t have those

Jan 29, 2022 at 6:34amWeb
Show threadaster Jan 29, 2022

if you have an air horn with a good compressor it can also run indefinitely in principle from what I’m gathering (subject to power and air availability)

it’s hard to find info on this one because I don’t think anyone wants to honk an air horn continuously because they are Very Loud

Show thread^,,^ Jan 29, 2022
@variance I think the air allows them to be very loud with relatively cheap components (since car batteries have relatively low peak power and the alternative would be lithium batteries or supercapacitors), so they probably will only run at full power for a short bit
Show threadvarveJan 29, 2022

@variance "so long as the battery has charge" is the key there...

I seem to recall that the first car alarms didn't shut themselves off after a certain number of alarm cycles, but would just honk the horn and flash the lights until the battery died. So they would definitely "run out of honk."

Didn't take all that long for the next versions of car alarms to have a self-shutoff.