FM Transmitter Circuit

[techno13th]

Hello,

FM transmitter circuit is one of the famous circuit for electronic development. So many DIY project involves this circuit. So when I looked into my Car Audio Fm transmitter circuit, obviously it has the same design with the basic circuit that I've found on the net. Most of the car audio FM transmitter has a fixed audio input jack. Of course the function is to received the audio signal from any Audio output. Is it possible for me to replace the audio input jack with electrec Mic ? So I can send voice signal to the receiver ?

 

[Shyamal]

Hi,
Transmitted signal frequency must be equal to the frequency decoder of the receiver circuit. If it is true then you can use such kind of frequency.

 

[mister_e]

Sure you can, but high likely you'll need to modify the input preamp or build an electret MIC preamp. Pretty simple task.

 

[techno13th]

The input audio jack has 4 terminals. I try to check the voltage and it reads maximum 2Vdc when I inject 6Vdc supply on the circuit. After I check the polarity, I soldered my electret Mic to it. Yes, I can hear a voice on my FM receiver but not clear and noisy.

Well other than amplifier... how to increase the sensitivity of the mic??

 

[4pyros]

Well other than amplifier... how to increase the sensitivity of the mic??

You need a preamp.

 

[Shyamal]

all is right