mic and Impedance matching

[larissam]

Hi,

I am working in a project, where i have a Microphone Electret with a impedance at the output of 2,2kohm. and a impedance matching (FET) where i am using Mosftet VQ1000J.

My target is to see at the output of the Transistor a sinusoidal signal from the microphone.
When i tried the circuit just the impedance matching with a signal generator at the input using
frequency 1khz, offset 1 volt and a peak to peak voltage amplitud 2 Volts. i got the signal i am looking for BUT when i connected directly to the microphone i dont get any signal at all.

I already tried the microphone alone and it works well.

I dont have to much knowledge about transistors and with audio circuits.
I know there are many things i am missing to make the connection between the microphone and the impedance matching work but i dont know which one should i look.

I dont know if the impedance from the microphone could be a reason why it doenst work.

any idea, i will be really grateful

thanks in advance

Larissa

 

[BobK]

Hi and welcome to the forum!

Typically, electret microphones have the JFET amplifier built in, and they need a power connection to work.

This article shows you how it is connected:

http://en.wikipedia.org/wiki/Electret_microphone

The output from the capacitor should provide a signal of about 5mV and go into a microphone preamplifier.


Bob