From: John Woodgate
Subject: Re: Help needed with audio mute circuit
Date: Fri, 20 Sep 2002 21:57:36 +0100
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Fri, 20 Sep 2002 21:01:27 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that LY wrote (in <%bLi9.2640$t
%firstname.lastname@example.org>) about 'Help needed with audio
mute circuit', on Fri, 20 Sep 2002:
>> Yes. Several European audio products simply connect a small-signal
>> transistor across the signal, downstream of a 1 k resistor if the signal
>> source is low-impedance, and feed a few hundred microamps into the base
>> to turn the audio off. There is very little non-linearity introduced
>> when the transistor is 'off'.
>Can you please clarify this for me. What do you mean by across the
>signal? Do you mean tie the collector to the signal and emitter to GND,
>and pump the base to shunt the output to GND to mute the output stage?
Yes. 1 kohm in series with the signal, then collector to signal,
emitter to ground. Apply base current to mute.
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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