How to make a direct microphone to speaker circuit?

Hello all,
I recently wanted to develop a circuit which picks up voice signals from a microphone and outputs it to a speaker.
As I recently started learning to build circuits, I was hoping to get a few inputs and tutorials on how to build one in a step by step manner.
Please help by giving instructions and not a circuit diagram as I am still learning.
Thanks for all your help!
Regards,
Microtest

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iceng3 years ago

You can see physically how this circuit is put together.

The author called it a radio receiver BUT he put the wrong picture on the page.

Clearly it is a fixed volume three transistor audio amplifier.

I back traced it and guessed at the capacitor values and the transistor type.

It may need adjusting but should work with an electret mic

If yours is a three wire mic let me know and I can change the input.

The reason I like this pic is it zooms so well for a neweby to see the wire placement....

mic3trans.jpg3-transist audio-amplifier-circuit.jpg
Etronix iceng8 months ago

Would this work using an 8ohm speaker?

iceng Etronix8 months ago

Not as well with a puny TO-92 case 2N3904 driver transistor...

iceng3 years ago

You can use a speaker to an identical speaker just straight wiring, NO electronics, No batteries !

Talk into one and hear it in the other in another room.....

BTW this set up is by-directional ..... Works either way and because there is no amplifier in the path there is no feedback Squeal .. Ever.....

You can use 2 paper coffee cups connected with a length of string as well, but it isn't going to work very well unless it is a straite line.

However the speaker to speaker works because the output of a speaker is much larger then the output of a microphone.

I was wondering who would pull that line out :-)

never one to fail you :-)

iceng iceng3 years ago

Some details of speaker operation.

The reason the receiving speaker is quieter is the resistance in the connecting wires .... So use heavier gauge wire.

spk2.gifspeaker to speaker.png
rickharris3 years ago

No - You can't directly drive a speaker from a microphone. the output from the microphone has to be amplified by an electronic circuit. Lots of audio amplifiers on line if you search.