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Amplified Ear help!!!!


ruden

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I have copied the amplified ear.

http://www.electronics-lab.com/projects/audio/023/index.html.

Can someone explain this thing? How it woks?
I am really curios :-\ about this "constant volume" thing that a signal with high or low amplitude can be levelled at the same point....

Please....

Thank you ;)

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i biult the amplified ear to but it dident work so i changed 2 of the caps to electros and did a bypass job and it worked  but i got some feed back but if tou want something that will do ok look at the parabolic mike circuit  and electret mike preamplifier somewhere in the forums , well ill post the one im refering to here it dose ok in amplifieing sounds to like the amplified ear would but this ones easyer to biuld

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Hi to all, I think too that Steven's curcit is better (it's easier to build), but it doesn't seem that it have a logarimic amplifier. It will increase hi signals with same coefficient as low signal and it will be to noisy.
If I am not wrong in first circuit exist the modul for logaritmic amplifing (in red quad). It amplifing low signals more then hi signals and in output all signals will be approximate of same intesity (("constant volume) 4 ruden).
This cind of amlifier is frequently used in radar curcit so dot in catode its same intensity for objects far of radar antenna as for clouse ojects.

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Hi DRulje,
Q4 is just an ordinary amplifier.
Q1's gain is controlled by its base current. With a low input sound level, R7 in series with R2 provides plenty of base current to Q1 and it has plenty of gain. Q2 amplifies the output of Q1 so that when a signal level is high enough at the output of Q2 to cause Q3 to turn on, then Q3 conducts.
With Q3 conducting , it and R6 in series with it make a voltage divider with R7, reducing the base bias current of Q1 and reducing its gain. C4 filters the DC gain control voltage and R2 converts the voltage into a current ;D

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  • 2 months later...

Hi
Audioguru explained the circuit perfectly.
In Communication circuit this is Called AGC(automatic Gain control). the best example of this circuit is in TV Tuners. when a TV receives high power, the AGC amplifies the signal a little and when received power is LOW the AGC Increases the Amplifier Gain.

In the main circuit C3 and D1 creat the Clamper circuit which shifts up all negative signal above zero. Clamper are very useful circuits.

But Does anybody know how is it possible to design a DC controlled Amplifier with OpAmps?

ThanX
Shahriar

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  • 3 weeks later...
  • 2 months later...

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