Hi Uludere,

If you're intending to use a PIC with ADC such as e.g. the 16F87* and you want to measure directly then it's only a question of the frequency you are dealing with and the speed of the PIC oscillator. If you are prepared to do a little circuit work and you don't need to read the frequency you can rectify the AC line and simply measure the DC component, which is easier and requires much less code.

It's no problem, though. Let me know what range of voltage and frequency you're interested in and I'll send you info.

Greetings,

Rob