Microphone Replacement

[electrocomp]

I have a circuit in which a simple microphone is used. The circuit is connected to PC with the USB interface as an input audio device (microphone).

Now instead of using a real microphone in this circuit, I need to replace the microphone with a simple circuit to simulate a fixed signal. In fact I want to see a fixed signal level in my software in the computer without any other change to my circuit. I only want to replace the microphone with an equivalent circuit that generates a fixed signal.

Please suggest me some as simple as possible circuits to replace with microphone.

 

[BradtheRad]

A typical microphone produces between 0 and 50 mVAC, depending on sound volume. Some types produce more, some less.

A substitute might be a sine wave generator, putting out between 50 and 5000 Hz, at 10 mVAC amplitude. You may need to reduce it with a potentiometer (volume control).

Or if you touch your finger to the signal lead, it will inject 60-cycle hum if you are near mains power.

 

[electrocomp]

Can anyone suggest a simple circuit to produce this sine wave?