How to measure the frequency of an ac signal and convert it to a voltage

Using Arduino Sensors
1

What are some techniques to measure the frequency of an ac signal and convert it to a voltage?

My specific need is to measure the frequency of ac power on one pole of an alternator.

Thanks!

2

You have to know what you want to measure. You talk of voltage frequency and power all are different things and you can not derive one from the other they are all independent of each other.

3

I'd like to scale the frequency measurement to a 0-5 volt signal for use as the input to another instrument.

4

Try one of the frequency counter sketches, use the measured value to drive a PWM output, and integrate it?