Re: small signal NPN transitor for muting microphone

Hello Frank

Thank you very much for the reply.

The switch is part of the microphone. About five meters away and will pick
up some noise. Actually the switch is part of the microphone. Two extra wire
comes out of the microphone.

My apology for no explanation for the diode.
I have now uploaded second image to explain why I need diode (Diodes).
http://www.psv.co.uk/MicMute2.JPG

I hope this new image will do some explanation.

My main worry is the diode. I think having this diode in pararal with
base-emmiter might reduce ON resistance of the transistor. In any case my
another worry is that, will transitor offer low ON resistance at very very
low current? Some quick search on transistor database gave me some basic
answer about ON resistance, But it only specifed at 3mA.

Thank you very much for your help.


"Frank Bemelman" <f.bemelmanq@xxxxxxxxxxxxxxxxx> wrote in message
news:43d3f052$0$21684$e4fe514c@xxxxxxxxxxxxxxxxxxxxxxxxxxx
> "RR" <RR@xxxxxx> schreef in bericht
> news:dr0pr4$g5t$1@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> I have posted a circuit at this address, please have a look.
>> http://www.psv.co.uk/MicMute.JPG
>>
>> What I am trying to do is, mute the microphone by using the transistor as
>> explained in the circuit. I can un-mute it by closing the switch. All
>> this
>> works fine on one unit I have modified. I need to modify about 200 units.
>>
>> My question is, can you see any problem with the circuit?
>> BTW new parts I will be adding, are:
>> one 4.7K register, one Transistor, one diode and a switch.
>
> What is that diode doing?
>
> Or, why use a transistor, diode and resistor? Just put the
> switch in series with the microphone.
>
> --
> Thanks, Frank.
> (remove 'q' and '.invalid' when replying by email)
>
>


.

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