Ok I have a PC-Board Condenser Microphone Element part 270-090 radioshack.

I have an old speaker that say's it is an 8 ohm , 2 Watt

The microphone electrical characteristics is
supply voltage 1 to 10 VDC
nominal suppy 4.5 VDC
Current drain 0.3mA (max)
signal/noise 60db (min)
sensitivity -64 +- 2db
Output Impedance 1k ohm.


How can I make it so when you talk into the microphone you here it out of a speaker .

I know P = 2 watts = VI = V^2/R => V = 4vdc => I = 0.5 amp
This means the speaker needs 4 volts and 0.5 amps of current to it.

I am unsure what I need to do to get the microphones out put in the range for the speaker.

I have a 9 volt battery and 1.2 volt battery.
Lots of resistors and capacitors.
Lots of different gage copper wire.
And some transistors I think both PNP and NPN.


For the microphone I am unsure what defineds how much current and voltage it will out put. Is say's that current drained is 0.3mA and output impedance is resistance + i reactance since it is real the impedance must be just 1k ohm resistance.

I know that humans hear in the 20 hertz to 20k hertz range.
So I am assuming I have to use some kind of capacitor , inductor setup.
To alternate the current back and forth and have the microphone effect the frequency in the hearing range to the speaker.

Sorry I am a little lost.
I know alot of different things but I am having trouble in determining what is important current, voltage , or frequency of ossilation ...etc etc

 

Do you want a prebuilt amp, or are you wanting to build one yourself?

 

I want to buid this from scratch.

Just want to be able to talk into the mic and hear it out the speaker.

 

The microphone is an electret one not a condenser one. RadioShack don't have a clue about electronic parts.
Its output level is about 5mV to 10mV into a high input impedance amplifier.
A speaker needs to be driven from a power amplifier.
If the microphone can hear the speaker then the sound goes around and around making acousic feedback howling and squealing.

An LM386 is a little power amplifier that can drive an 8 ohm speaker to 0.45W at clipping when the 9V battery is brand new. A cheap little clock radio will be louder. You can make your own LM386 amplifier with 4 transistors and many resistors, capacitors and diodes.
The LM386 can be set for a gain of 200 then its output will be fine if you talk loudly and closely to the microphone. An added transistor can amplify it more.

 

Here is a link to some microphone preamps - http://sound.westhost.com/project13.htm.

You will need a preamp before the audio amp.

 

Well I don't have some of the parts given in the preamp digram but I do
have an op-amp from radio shack. Could I use an op-amp in place of the preamp digram.

I think the op-amp was a LM386 but I cann't find the package that I had it's characteristics.