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What IC should I use to make a microphone to speaker amplifier?

I want to make a microphone amplifier. I have tried using the lm386 Ic but it performed poorly.
It would be helpful if anyone could give me a hint on what IC to use with or without a corresponding schematic.



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iceng5 months ago

Try this Bowden circuit; a speaker is an electromagnetic machine and can do sound to electric signal as well as electric signal to sound...

http://www.bowdenshobbycircuits.info/opamp.htm#int...

"Low Power Op-Amp - Audio Amp (50 milliwatt)


The example below illustrates using an op-amp as an audio amplifier
for a simple intercom. A small 8 ohm speaker is used as a microphone
which is coupled to the op-amp input through a 0.1uF capacitor. The
speaker is sensitive to low frequencies and the small value
capacitor serves to attenuate the lower tones and produce a better
overall response. You can experiment with different value capacitors
to improve the response for various speakers. The op-amp voltage gain
is determined by the ratio of the feedback resistor to the series
input resistor which is around one thousand in this case (1 Meg / 1K).
The non-inverting input (pin 3) to the op-amp is biased at 50% of the
supply voltage (4.5 volts) by a couple 1K resistors connected across the
supply. Since both inputs will be equal when the op-amp is operating
within it's linear range, the voltage at the inverting input (pin 2)
and the emitter of the buffer transistor (2N3053) will also be 4.5 volts.
The voltage change at the emitter of the transistor will be around
+/- 2 volts for a 2 millivolt change at the input (junction of 0.1 cap
and 1K resistor) which produces a current change of about 2/33 = 60 mA
through the 33 ohm emitter resistor and the speaker output. The peak
output speaker power is about I^2 * R or .06 ^2 * 8 = 28 milliwatts.
The 100 resistor and 47uF capacitor are used to isolate the op-amp
from the power supply and reduce the possibility of oscillation.
An additional 22uF cap is used at the non-inverting input to further
stabilize operation. These parts may not be needed in such a low
power circuit but it's a good idea to decouple the power supply to
avoid unwanted feedback. The circuit draws about 1.2 watts from
a 9 volt source and is not very efficient but fairly simple to put
together. The circuit was tested using a couple 4 inch speakers located
a few feet apart (to reduce feedback) and a small pocket transistor radio
placed on top of the speaker/microphone as an audio source."

Click pic 2 see Image...

intercom.gif
MrB12 (author) 5 months ago

Thanks everyone for your answers! They have helped me further understand how microphones work I will sure take them into account the moment I decide to continue with the project.

Rajkumar25065 months ago

The microphone has output voltage in micro volts(uV).It is not enough to be amplified only by using audio amplifier.Before you connect the microphone to audio amplifier some preamplification has to be done.You must connect the microphone to CE amplifier for preamplification and then you should connect the output of CE amplifier to audio amplifier.CE amplifier will amplify microvolt(uV) to Volts.Its better if you connect audio amplifier after CE amplifier.

microphone----->CE amplifier----->Audio Amplifier

that is why I suggested the

Electret Microphone

which is a class piezo sound elements that put out millivolt signals

http://www.goldmine-elec-products.com/prodinfo.asp...

iceng5 months ago

Use the LM386 and a piezo microphone for the signal.

Click the pic to see the whole image.

Gain20LM386.bmp
LM386.pdf264 KB
MrB12 (author)  iceng5 months ago

Will it work if I use it to amplify a person´s voice?

iceng MrB125 months ago
piezo mike.jpg
iceng iceng5 months ago

Assuming you build it correctly.