OT: Simple electronics question...

From: der Mouse <mouse_at_Rodents.Montreal.QC.CA>
Date: Wed Aug 4 17:03:40 2004

> I have a little Timex clock radio. Works great, except when I want
> to fall asleep to the radio, I need to turn it down so as not to
> disturb my wife. Problem is, that the volume control isn't sensitive
> enough at the low volume I want.

> So, my thought is to put a resistor on the positive lead of the
> speaker, which (I think) would lower the overall volume output, and
> give me a wider range to adjust the volume to a quiet level.

Well, speakers mostly don't have polarity on their leads. At least not
voice-coil speakers such as you find in "little clock radio"s.
(Switching the leads will reverse the direction of voice-coil movement
for a given current - but that difference is approximately inaudible.)

You could do that. But you might be better off frobbing the
volume-control circuit itself. The volume control is projbably a pot
with one side grounded, one side driven, and the variable tap taken to
drive further electronics. Inserting a resistor in series with the
non-grounded side will do something like what you want.

Either of these approaches runs a risk of creating impedance mismatches
between the driving circuit and the driven thing. Which way introduces
less distortion depends on the circuit - though I must confess that I
would expect the distortion introduced by this mismatch to be far less
than you get from other causes in most clock radios.

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Received on Wed Aug 04 2004 - 17:03:40 BST

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