Electronic Speakers

Hello guys,
I have a question? Although it is childish but let me ask. I wanna know
-How does a speaker produces SOUND in correspondence to Voltage level at input. How does the pitch of sound varies w.r.t. input voltage.
-How does CRT Monitors produce display in correspondence to voltage levels transferred to them.
Plz tell me a link from where i can get to know about working of the various electronic devices.
Regards
BABAR

https://en.wikipedia.org/wiki/Loudspeaker
R u from Pakistan?

Yes i m pakistani

Yes, i m from karachi, pakistan

I know Wikipedia has expalined it but I'll sumerise it.

• Speakers require an AC voltage.
• The frequency of the sound = the frequency of the AC waveform.
• The higher the voltage the louder the sound.
• The waveform of the sound produced = the waveform of the AC voltage.

Speakers require an AC voltage to generate pressure waves but DC coupling is substantially preferred. Most simple amplifiers are decoupled with a capacitor to the speaker to remove the DC bias as speakers don't react well to it (lots of heat and single ended clipping), but this completely eliminates power transfer at very low frequencies (sub audible) and substantially muffles low audio frequencies. The lower the frequency the more it's affected. DC coupling eliminates that problem.

Understanding the exact relationship between the driven voltage at various frequencies and the perceived audio level is pretty complex as it's not linear and there are several points of non-linearity, including the amp itself, the speaker cones mass. Air's mass, the enclosure the speaker is in, the objects near the speaker, the position of the listener in relation to those objects not to mention the listener them self! =) It's a real bear to make any sense out of it.

People will spend many multiple hundreds of percent over the actual cost of a device in the audiophile market simply because they don't understand how a speaker actually works or how they're affected and affect their environment.