sound to current or voltage amplifier

[millman]

I am looking for help to design an amplifier which will take the output from a microphone and amplify it to a milliamp or millivolt signal suitable to input to a process panel meter. The meter will accept 0 to 20 milliamp 0 to 199 millivolt 0 to 5 volt 0 to 10 volt etc and has a 10 or 24 volt exitation output. The device is required to control the loading of an industrial mill, the sound output of which is proportional to the load and the panel meter is used as it has configurable output relays and other bits built in.  It may be that there is an audio amplifier available that will do the job.            best regards mark.

 

[audioguru2]

Hi Mark,
Welcome to our forum. ;D
It is difficult for me to know the output level of your microphone without knowing its type nor sound level to be picked-up. The mic will need a shielded audio cable to connect to an amp.
A simple amp is an LM386 which is an IC with only 8 pins. It has a choice of gains, works with a 10V supply and has an output voltage of up to about 3V RMS.

View attachment 37787

 

[millman]

Hi Audio guru.

                      thanks for the amp diagrams, the microphone I will use will probably be something salvaged from an audio system. What I will do is aquire an amp connect it to the mic run the machine and see what value the amp output is and then scale the panel meter accordingly. The panel meter has an input filter so I would assume this can be configured to smooth the response of the meter to what probably will be a spiky input signal.  Thanks again I will let you know how I get on  best regards Mark.