I need a to make a circuit that measures signal strength, something for a amp project. I need to know in how many volts my output is. Thank you so much for helping.

 

What kind of amplifier is it?

What is your output signal?

 

Sorry if I didn't explain myself clearly. I want to make a sonar distance meter (just for a meter or two) I will have a speaker transmit a 50khz signal and then the mic listens for the echo. I hope by listening to the echo I can determine how far away the object is. I will use a PIC16F57 to do all of that, my only concern is how get the highest part(in voltage that is) of the signal.

 

You mean you want a peak detector?

To measure the distance you need to measure the time the sound needs to travel from the speaker to the mic.

 

To measure the distance of a few meters, line of sight, I have an idea.
Use a LED transmitter/receiver and an audio transmitter/receiver.
At the receiver end, use the LED circuit to start the timer and the audio circuit to stop the timer. Convert the result to distance.

 

If you use the signal strength of the reflected signal then you are measuring how smooth, hard and aimed-at-you the surface is, not just its distance.