Hi all,

I'm trying to control the PC speaker (motherboard beeps etc) volume
using PWM (software-driven PWM from a PIC) but I'm not really sure now
to design the circuit.

Since the PC speaker is just a squarewave output (unless I'm terribly
mistaken) I thought about feeding the PWM into a pair of transistors
to charge/discharge a capacitor (to smooth out the PWM) and then
connect the PC speaker signal to a transistor that turns the output on
or off, using the capacitor as power source. Does this sound OK or is
there some obvious better way of doing it? Maybe using two
transistors, one taking input from the sound input and one from the
smoothed out PWM (plus a pot to control the volume range) all running
from the main power bus? (that way changes in the sound signal
shouldn't vary the load on the capacitor and thus the volume)

Regards,
-- 
Hector Martin (hector@marcansoft.com)
Public Key: http://www.marcansoft.com/hector.asc

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