Sound Amplifier

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cs200939

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hi i need a simple amplifier circuit that takes sound input through an electret microphone and amplifies it so that it can be out put loud through a 75 watt small buffer.impedence 8 ohms.i dont want to use high power supplies please.thank you
 
hi i need a simple amplifier circuit that takes sound input through an electret microphone and amplifies it so that it can be out put loud through a 75 watt small buffer.impedence 8 ohms.i dont want to use high power supplies please.thank you

75W is a fairly high powered amplifer, not a 'small buffer' - as 75W in 8 ohms requires 70V p-p you're looking at an 80V supply rail at over 1 amp.
 
Yeah it sure is...actually i just need to show that i can actually output on a speaker whatever i say on a mic..i had this buffer lying around for quite long so i thought why not put it into use but seems like it wont work..ok umm ive some speakers that are with in 0.5 to 1 watt with 8 ohms impedence.can i use them?.if yes then what are the schematics?.if not then kindly suggest a suitable speaker with suitable specifications that allows me to amplify my sound so that anyone like 10 meters away can listen to it please its part of my project ..thank you
 
the circuit in the link sure looks easy enough but what did you mean by "Just feed that to a small IC power amplifer, such as an LM386"?.cant i just attached the output to some speaker?..mind me i have very basic knowledge of electronics
 
the circuit in the link sure looks easy enough but what did you mean by "Just feed that to a small IC power amplifer, such as an LM386"?.cant i just attached the output to some speaker?..mind me i have very basic knowledge of electronics

Speakers need feeding from a power amplifier, not a preamplifier.

Add something like this to feed a speaker:
 
And whats with this VR1(100K "A" taper pot)....its jsut a simple variable resistor right?..of range 0 to 100 kilo ohms?..i am sorry but this is the first time i am using these components in full fledge..before this i was jsut restricted to theories and definations
 

Yes it is a 100kilo-ohm variable resistor. pot means potentiometer, or simply a variable resistor.
 
But the output of the LM386 amplifier with a 9V supply into an 8 ohm speaker is only 0.45W which like a cheap clock radio. Is that loud enough?
 
well if its loud enough to be heard with in 1 meters of radius in a quite room then its all fine.what do you think?
 
And i found this circuit digram on some website.will it also work if my input is an electret microphone?..i mean is this jsust power amplifier or power amplifier with preamp too?.im sorry i dont have any knowledge about this unless i try all this out thats why may be this is silly question:|
 

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and whats the theory behind the two variable resistors in the circuits i mean one in the preamp circuit and one in the power amplifier.i know one of them definately controls the volum but which one and what does the other do?
 
and whats the theory behind the two variable resistors in the circuits i mean one in the preamp circuit and one in the power amplifier.i know one of them definately controls the volum but which one and what does the other do?

The power amp one is an attenuator, a standard volume control.

The one in the preamp sets the gain of the preamp, to match your specific mike and how much gain you want.
 
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