Re: PC speaker

[Helge Hafting <helge.hafting@aitel.hist.no>]

Jan Engelhardt wrote:
> Since you can set the x86's crystals frequency from 1193182 to 18 Hz
> (PIT_TICK_RATE / 1 to PIT_TICK_RATE / 65535) [*], you can never really
> bust it. But even then, what would a speaker do it was constanly given
> +5V? (I _suppose_ the other level is 0V, not -5V -- makes for easy 
> design.) That's IMO just like a sound file with volume(x) = 1, nothing 
> spectacular if you ask me.
>   

I guess a motherboard don't provide enough current to
burn out that speaker.

But generally, speakers that handle some maximum
alternating current *will* burn out if you give them
the same amount DC.  This becasue speakers
are designed to handle AC - some of the energy is dissipated
as sound waves, some as an alternating magnetic field,
some has heat. And the speaker moves, so moving
air helps cooling it.

A speaker getting DC converts all that current into heat only,
and it stands still so no extra cooling.  So it burns out.

Helge Hafting