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The Microphone

Do you know it's workings? (January 2005)

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RT
rts Founding member
Got a message asking for my help. I've forwarded it to people who know a little more than me, and thought you might be able to help too...

I need to analyse a microphone pre-amplifier circuit, in order to show how it operates.  At present I have not got the ability to do that, but it is imperative that I do do it.  I don't know whether you can help, but it's certainly worth a try. 

Basically the circuit is a balanced input, single ended output microphone amplifier, which is made up of two main stages.  The first of the stages is made up from a combination of transistors(which I just can't understand at present), and this is followed by a differential amplifier (op-amp) with a fixed gain. Sounds simple enough!?

What I really need to do is show how it works from principles (i.e. ohms law, kirchoffs laws etc.??).  I've attached a copy of the circuit.... 

And I've uploaded that copy. It would be great if you can help.

http://www.rp-networkservices.com/tvforum/uploads/help.gif
IS
Isonstine Founding member
I'm sorry, but we're not going to do your physics homework for you.
RT
rts Founding member
German and Russian student here. If anyone could shed some light on the above though, it would be appreciated.
SL
SteveL
You (or someone) appears to have downsized it so half the values are illegible, and the negative output rail's disappeared. Do you have a non-squished version?
RT
rts Founding member
I do. I had to scale it down for the upload service. Sorry, I did not realise things had gone missing. If you could PM me your email address, I will send it over. And if anyone could host the actual size one (not much bigger) that would be great.
SE
Square Eyes Founding member
You know, I've tried, I really have. But I just cannot find the TV presentation content in this here topic.

Therefore I recommend instant closure for being off topic and a formal warning.
RT
rts Founding member
Square Eyes posted:
You know, I've tried, I really have. But I just cannot find the TV presentation content in this here topic.

Therefore I recommend instant closure for being off topic and a formal warning.

Thank's for that SE.

I would like to say though that technological discussion has taken place here many a time before, and the microphone is a popular instrument in both radio and television.
SL
SteveL
http://stevel.hopto.org/files/tvf/rowcircuit.gif

What is it you're looking for? Just the function of each section, or a breakdown of what each component's job is?
RT
rts Founding member
The writing in the italic at the start is all the information I have. I've emailed the full sized diagram to you Steve.
LL
Lottie Long-Legs
rts posted:
Got a message asking for my help. I've forwarded it to people who know a little more than me, and thought you might be able to help too...

I need to analyse a microphone pre-amplifier circuit, in order to show how it operates. At present I have not got the ability to do that, but it is imperative that I do do it. I don't know whether you can help, but it's certainly worth a try.

Basically the circuit is a balanced input, single ended output microphone amplifier, which is made up of two main stages. The first of the stages is made up from a combination of transistors(which I just can't understand at present), and this is followed by a differential amplifier (op-amp) with a fixed gain. Sounds simple enough!?

What I really need to do is show how it works from principles (i.e. ohms law, kirchoffs laws etc.??). I've attached a copy of the circuit....

And I've uploaded that copy. It would be great if you can help.

http://www.rp-networkservices.com/tvforum/uploads/help.gif


Not sure why, but the diagram has reminded me of Make A Chip for the ZX Spectrum Shocked

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