Right now you can squeeze 6W of power through the speaker. If you are using a standard 8Ω speaker then it could easily cause a substantial voltage drop in your power supply. You could build something like this FET amplifier to get a lot of sound without causing a short on the power supply.
Im lost. If my FET is switching from 0V to 12V how can the signal be amplified?? And is an Hbridge really better? what are you talking about when you refer to the DC component of the coil?
Im lost. If my FET is switching from 0V to 12V how can the signal be amplified?? And is an Hbridge really better? what are you talking about when you refer to the DC component of the coil?
The little BS170 did not switch from 0V to 12V because its on-resistance formed a voltage divider with the 8 ohm speaker. Then the speaker got 1.6V to 12V.
The BUZ11 has a much lower on-resistance so the speaker got 0.05V to 12V.
A full H-bridge is like a bridged amplifier. Both ends of the speaker are switched oppositely so the effective voltage swing is doubled then the effective current is doubled then the power is almost 4 times more.
A speaker works with AC. A positive swing when a negative swing. It works best with AC.
0V to 12V is DC, not AC so the peak current is doubled and the speaker voice coil assembly might run into its magnet structure.
A full bridge feeds AC to the speaker.
I was pressed for time and posted the first circuit off of Google, sorry I should have been more clear.
I was simply trying to find a way of isolating the speaker from being supplied by the full 12V and causing basically a short if the FET was left in an on state somehow.