Peter L. Peres wrote:
>                     +unreg
>                       |
>                       C
>                   +---B NPN
>                   |   E
> mcu out 5Vpp o----+   +---c1----+
>                   |   E         |
>                   +---B PNP    speaker
>                       C         |
>                       |         |
>                      gnd       gnd

Note that this will have a significant deadband around the zero audio
level.  This doesn't matter much if you just want make some beeping
sounds, but music will sound really bad, and voice will sound distorted
especially at low volumes.


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(978) 742-9014, http://www.embedinc.com

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